Here is another installment of exTRAPaganza, our Thursday over-the-top trap series.
Area of effect spells seem to have no effect anywhere.
At the bottom of this cave complex is a large cave. In the center of the cave are several large stone coffers. These coffers are full of treasure but there is a catch.
When a coffer is opened, that coffer becomes ground zero for every area of effect spell cast in the cave since a coffer was last opened. In addition the the party’s spells, other spells go off as well. There will be d8 levels of spells (so if a 6 is rolled, there will be level 1-6 spells). There will be d4+1 spells of each level, randomly chosen as long as there are area of effect spells. All the spells happen at once.