With people saying how delicious mystia is this was bound to happen

No. Bad Rumia, bad. Friends are not for eating.

This is why Rumia must be kept supplied with meat,candy,snack cakes and other foods at all times.
If she goes hungry too long she starts trying to eat people.

I guess all the talk about Mystia getting eaten all the time made Rumia think that Mystia respawns.

Either that, or this is about the other kind of eating, and Rumia doesn't realize that it's far too hot. Can't really tell, given the look on her face...