Secret Jabbi Easter Eggs - Paper Mario: The Thousand Year Door (Switch)

During Chapter 2, you can find Jabble the Jabbi hiding inside of the item shop, if you talk to him (and aren't mean to him) he'll join you for the rest of the Chapter.
Also, if you go to a specific bush post-Chapter 2, you can find a Jabbi baby (who may or may not be Jabble) who will give you a perfectly normal mushroom.