Segaworld Sydney also produced some shirts to buy as souveniers when you went. Today, they're all collectible. This one is blue with hot green cuffs and collar. It uses the rather unfortunate 'foreward facing' Sonic stock art which is never that flattering. He's pasted over a 'hypnotic' hot green spiral design and it says "Can't catch what ya can't see!" though, with all the hot green going on with it, you're sure to see this.
This Segaworld Sydney tee has the slogan "Can't Catch What Ya Can't See", then ironically shows a Sonic face for you to see. Notice the odd bit of shading under his nose like a little triangle. This also has text on the back, but no picture. (That's pretty unusual) The back says "Way Cool Lil' Bro", which, you would think would have Tails or something, but randomly, it just doesn't.