A Mystery Magazine?
Not really, it's actually a comic. This was given away around the time of Sonic 1, and was in the Disney Adventures Magazine of the times as an extra/insert type item. Since Sonic wasn't really famous yet people didn't know to look for it/keep it.
The image here was originally published by the website I09, to illustrate an article about the "Sonic the Hedgehog" gene (it's a real sceince item that you can look up). So the site didn't know what the item was either & the article wasn't about media. It's the old poster art for Sonic 1, with a "comic book like" little stamp in the upper left, which just says "Fall Sonic the Hedgehog 1991 Sega" The little number at the bottom is "Issue 1", there are prices below it & the Genesis logo is in the middle.
What it actually is, is a mini-comic "origin story" for Sonic that they made up to 'Americanize' him. Which origin is it? The Ovi Kintobor / brown Sonic, Evil Emeralds one that was retconned away later as it didn't make sense in a mass of places.

"Frictionless Shoes" (yes...can't get traction and never run again) & that they thought the name "Eggman" was too wierd so instead they had a regular guy spilling a drink while eating an egg and becoming egg-shaped because that's somehow less wierd & more acceptable to kids than a guy with a strange name. However, this is also thought to be the item that gave the Fleetway Comic the names of some of the supporting cast like Johnny Lightfoot the rabbit. Want to read the comic & know more? Read at Sonic Retro's Sonic Mini Comic Origin . Info from Sonic Retro & mystery solved by Chey TheHuman & Misteryt1