overworld effects

[Prominence]

I'm making overworld rooms persistant. When you collide with an enemy you go to a battle room. When I return, how do I make the enemy I just went to battle with execute a script? (well, just change sprite then die) and not every other enemy?

[IsmAvatar]

you could store its ID in a global variable. then when you return, if you killed it, destroy the object with id of the global variable.

[Prominence]

well, after spending over 3 hours I managed to get a too complicated ID thing working.

[IsmAvatar]

it should be somewhat complicated, but not overly complicated.
I'd think a simple on collision, set variable, set alarm, and go to room. On alarm (this occurs once it returns), check the results of the battle; if won, destroy object with id of variable

with (global.battlewith) { instance_destroy() }