Pokémon Emerald looks a bit different when you corrupt the file you play on. But that's not a bad thing.
Grass may turn to water. Pokémon might turn into giant question marks. And, sometimes, your character can't decide whether or not he wants his head actually on his shoulders. It's goofy glitches like this that make Vinesauce's "corruption" videos so great:
My favourite thing in here is all the f**ked up Zigzagoons... or maybe it's the fact Vinny can't seem to leave the starting area of Pokémon, thanks to how f**ked up this version of the game is. Heh.
[Vinesauce] Vinny - Pokemon Emerald Corruptions