Petrie took a dare from Chomper to eat some mushrooms. Unfortunately, Petrie is allergic to mushrooms...
Ducky: Oh no no no, this is bad! Remember the last time you ate mushrooms? You were in the bushes for four hours! We need to get you back to your nest, we do, we do!
Petrie: Me never taking Chomper's dares again...
Cera: Pardon me while I have words with that little biter.