[quote=@Rilla]
This can be rectified for future fights by you, if you haven't already, explaining what is affected. 


Things magically summoned? Anything manipulated by magic(sans PCs)? 

Things like that. Otherwise, it'll always be up for interpretation what can be and what can't be. And then, it'll come down to you having to decide right then and whatnot.

IN your example that fire would be magic, for sake of being magically summoned. But if the fire were already there, then it wouldn't be magic fire. 
[/quote]

Generally if magic is being used to manipulate it, or control it, obviously there would be magic in it. People don't always agree on that though.