ZDoom

Fixed. And just like I suspected, adding that check would have broken the entire thing.
The problem here was that when being called from ACS, the origin can be null - but still needs to be able to resolve the player constants to the actual player.

	if (!origin)
		return nullptr;

This crash happens because "origin" is nullptr in function *COPY_AAPTR in actorptrselect.cpp. (line ~65 or so)

Putting this at the beginning of the function fixes the crash, but I am not sure this is the correct way to handle it, so I am posting it here instead:
[code]
if (!origin)
return nullptr;
[/code]

Download link: [url]https://github.com/Kizoky/Mr_SmileyII/blob/master/maps/MAP01.wad[/url]
Crash report: [url]https://github.com/Kizoky/Mr_SmileyII/blob/master/CrashReport.zip[/url]