Play Sonic Lost in Mario World Online
Sonic blasts through Mario’s world like he owns the place—weirdly stiff jumps at first, but once you’re rolling through warp pipes and dodging Goombas, it clicks. The mashup’s so ridiculous you’ll grin when Tails randomly photobombs a Koopa Troopa.

Note: Right click and select full-screen for best experience
So Sonic’s just minding his own business, right? Taking a chill run through Green Hill or whatever, when bam—weird blue portal shows up. Classic Sonic move: he doesn’t even hesitate, just dives in. Next thing you know, he’s stuck in some pixelated Mushroom Kingdom nonsense, dodging Goombas instead of badniks. The controls feel a little stiff at first (gotta get used to Mario-style jumps), but once you start blasting through those warp pipes at full speed, it’s weirdly satisfying. Also, seeing Sonic in Mario’s world is just… funny. Like, he doesn’t belong there at all, and the game knows it.
Honestly, half the fun is spotting all the little details—Bowser’s castle with Sonic’s logo slapped on it, or Tails popping up in places he definitely shouldn’t be. It’s janky in that old Flash game way, but in a charming, "this shouldn’t work but it kinda does" sort of vibe. Just don’t expect polished physics—Sonic’s spin dash sends him flying way farther than it should, and I’m not complaining.