Mega Bot Line
This line is named for the "Mega Bot" which you can build if you collect all the figures. Each figure comes with 1 piece of the robot, which then snaps together. However...this series has a deceptive twist!
There are actually SIX characters in the line (not including the mega bot). For some reason, there's a duplicate Sonic. He comes with a 'catapult' and 'exploding robot' accessory. This Sonic has a different leg pose, flat feet and open hands. The MegaBot one has fists and a bent foot. It is a mystery as to why the spare Sonic was included on the line, as he makes it tricky to put together the RBX-D05 robot....which you can see below.

Look carefully at the box to see the action figures you can collect! You can see who is in the line (Sonic Knuckles Tails Shadow Amy) and you can also see Eggman's RBX-005 mega robot all assembeled.
You can put it together if you buy ALL the characters, who come with 1 piece of it. You can also see Decoy Sonic on here, and his "breaking action" gun-robot and "X" shaped catapult. It's mentioned on the back, but what they don't tell you is, that if you buy this by mistake, you won't get the torso, and can't build the bot.

It claims they are all fully articulated, but we now know this isn't really true for the MegaBot Line. It also claims to be "Series 1" which implies that they want at least one more sereis.

Keep checking your Toys R Us and KB Toy stores as well as Sonic Gear to bring you exciting news and photos first! So far, only Toys R Us has these. Expect a price of about $5.99 each.

Notice the quality of his hand sculpt. The fists are realistic, detailed and nice.

Here's their first Sonic. This is the guy that comes with the most crucial piece of the Mega Bot, but unfortunatly due to his double, he may be squeezed out of stores!
The head is made of a semi-soft matte finish plastic. The body is solid and hard, while the legs and arms are PVC-like. The colors are all painted on, except his shoes. Watch these guys for paint-errors! As you can see, his poses are rather limited by his feet and permenently bent legs. His expression is OK, but he's stuck looking up.

All the figures seem to be trying to imitate the old ReSaurus ones, joint-wise. But they don't compare...The shoulder, and hip of each figure has a sort of ball-joint which is too small to do it much good. They are also limited by the sculpt of the leg AROUND the joint, and so don't actually seem to 'action' much. ReSaurus had a type of joint which could rotate, but also raise, and smooth areas around it to allow more motion. These are simple.
Credit has to be given though, because the Sonic X characters own designs are...rather unstable with huge heads, stick legs and large hands. None lend themselves to balancing very well.

Here's the culprit!
Why is this figure on the mega bot line? It's like someone had an idea that HAD to be included somewhere, so here it is. The "X" thing is a catapult. You can set something on one side, and slam down on the other to try and send it flying. It's MEANT to make Sonic 'jump' onto the little widget gun thing you see there...but it barely propels him an inch--unless you risk breaking it.
The gun turret thing appeared in Sonic X episode 1, and shot Eggmans' machine by accident, leading to the chaos control transport.

The finger of his hand is touching the gun tip in this photo, so you can see the size. The robot is meant to fall apart...so naturally it's nearly impossible to keep it together.
Also WHY is there Engrish on the package? They already forgot Missile Wrist's name, now they can't formulate a proper sentance? Hmm....
His single pose looks rather cool, though.

Engrish Alert!
"Place your Sonic the X catapult and activate jumping action. Aim at robot and watch Sonic land on it and activate it's exploding action."

Of course what you've been waiting for...the Mega Bot! This is the RBX-D05 robot you can build if you manage to buy the right sonic. Here 'interesting hands' Sonic illustrates the size, along with a pencil.

The claws of the robot can open and shut, but won't rotate. It has shoulder, knee and up/down ankle joints. The head turns and the hips can rotate the legs. You snap the pieces in by pushing the buttons visible on the back. You can also take him apart that way. There are no stops on the elbows so they're pretty much 180+ range of motion. It's pretty well constructed and nicely painted. This definately deserves the title "Mega Bot"!
In all, the Mega Bots line is much nicer than their 6 inch figure line. The sculpts are over all better, and it has the range of characters people want to collect. The mega bot itself is a fun concept, but this is jeopardized by the "Red Herring" catapult figure. Since Sonic has the torso of the robot, if you miss getting the right one, you'll NEVER build the bot, and be stuck with boring pieces. The Red Herring is so EASY to mis-represent on Ebay and in online stores since it's "MegaBot" labeled, but has nothing to do with it. It also replaces the torso figure in the store, limiting your ability to buy the right one. Toy Island is putting forth an effort, and this line is proving it.

Be on the look out if you are buying anything on the Mega Bot Line in 2008, late 2007.
Why? Varient figures abound now! Toy Island is messing around with this line for an unknown reason. Just look at these interesting photos! The most noticible one is Knuckles and his giant twin. Why is one so much larger than the other? They come in identical packaging, but the 2nd one (larger size) didn't start showing up until long after the initial release.
The next thing you may notice is the Sonic figure. Why is one looking up? Because he's got the Space Fighters' head! Yes, for some reason they felt the need to change out his head mid-production. The Amy is more subtle, but the 2nd one has smaller green spots for her eyes. Comparison photos thanks to Retro. The photo on the far right shows one MB Sonic with a longer neck than the one to the right. The difference is rather a small one but it is interesting. Far right photo by LarryInc64

Notice something wierd about this box-back on the right?
Amy Rose is missing. This box was used later on...but does it mean Amy was excluded from some of the later releases of this line? Clearly, she made it out twice (see above photo) so why would they erase her from the back-card? It is unknown if this will contribute to making this figure more rare or not. And if they were to drop a figure, why wouldn't it be the 2nd Sonic (with 2 accessories) as surely he would be more expensive to make. You'll see THREE Sonics there, 2 of which were normally released (torso one, X launcher) and the last (top) one you can see at the bottom of this page. A curious development. 

Here is a rather ordinary looking item that is either a switch or a mistake. This package has 'open hands/interesting hands' Sonic but it also contains a Mega Bot arm piece. Usually this Sonic came with the plastic 'x' launcher thing. It's not the FEVA one either, because they never recieved this Sonic at all. Did ToyIsland change their mind late in the game and dismiss the X-launcher one? Is it some type of error? No matter the answer, it's still interesting to see. Discovered by Berzerker.

Owned by larryinc64

FEVA Toys of the UK was in charge of the figures in the UK and presumably EU area. This is what the back of their boxes looked like, and you'll notice they never included that confusing launching X Sonic thing and gun turret. (This also means no 'interesting hands' Sonic, either) The good Shadow head is shown on the box back as well, so you'd know what you were getting.
It's also been reported that the 'good head Shadow' was on some VERY early releases of the line in the USA as well before being replaced by the worse one. However, you would have needed a store close to a distribution point to get one before he was phased out. 

Whoa, what's this!
A 2015 discovery brings this super strange & unheard of Mega Bot item! Clearly it was packaged...clearly 1 was produced, but what's going on?

As you can clearly see above, and in the Sonic X show, the "Mega Bot" was always blue & green. However, the Mega Bot piece here (head/torso part) is CLEARLY cast in candy apple red shimmer/pearl plastic with gold accents! And, if that wasn't strange enough for you, Sonic himself is shimmer pearl too! Everyone knows the "Metal Force" figure line was done in this shimmer paint, but Mega Bot was never anything to do with that. The Sonic figure may be painted (look, even his gloves & shoes) but the bot plastic is apparently actual glitter-plastic. The box is identical (even shows correct bot) with all the same features listed.
Do you know what's going on? Write in for credit on this big mystery piece!
Photo by Culture Pop Toys

Figure was originally aquired when a Sega Licensing branch office closed. They sold off privately several prototype items, rare items & first edition items. Licensing branches tend to have stuff like that, but they keep it around the office in a type of collection. Shutting it down released the items to a few collectors.
Mega Speculation:
This was a 'chase' figure, a "1 per carton" variant special figure meant to entice collectors*.
This was meant to be a "variant" for a Mega Bot RE RELEASE planned if the first MB release did well (makes sense because MB1 did ok, but they loved the idea of sparkly things & made Metal Force figures later)
Look on Prototypes 1 of SonicGear , and you'll see the GOLD Megabot, which does exist, but was photographed at a Toy Fair, and thus was likely never actually packaged & sold...unlike this one
Speculation 1 contributed by Sonicthehedgehog9908

The figure as an error or "something they didn't mean to do" is VERY VERY unlikely because it actually got packaged and sold. This isn't like "2-left-hands-Shadow" or "wrong name Knuckles", this took real effort, someone did this deliberatly.

*Chase figure is indeed possible but may have been scrapped because it would have been incredibly annoying/impossible to collect FIVE chase figures to put together a matching all red Mega Bot. Instead of enticing collectors with a thrill it would have upset everyone, because if you were making the reuglar bot, you wouldn't want some random red arm. Or, at one per carton, maybe nobody could ever assemble the whole thing because random moms & dads could unknowningly buy the variant and just toss it to a 5 year old, never to be seen again.

Did you suspect the Red Mega Bot package above might have a different or unusual box back? If so, you're right! Look at ALL the Sonic figures pictured here, they all have the same 'looking up' head which is wrong. It's also missing Amy Rose & likely incorrectly has 'leaning' Sonic twice. It's no surprise that the box back could be different, but it's very interesting to confirm it.