Player A controls a Possibility Storm. Player B casts Zoetic Cavern for its Morph cost. What happens as Possibility Storm triggers?

~Note: myself and other l1's discussed this and an l2 I discussed with recommended posting this on here, it was a fun hypothetical situation we came up with :) ~

Possiblity Storm cares about what card types Zoetic Cavern had while it was as a spell on the stack, not what types it has when it's in the exile zone. Since the face-down morph spell was a creature and no other card types, Player B will exile cards until he or she exiles a creature card, and the rest of the resolution will proceed as normal.