Foliaath

Foliaath is the mini boss version of the kryebaby knatcher. It is smaller though, and normally spawn in oak forests and blend into the ground. They are purple and red and before the fight, camoflauged, only their leaves show. They are optional, have 30 hp , and drop a foliaath seed. You can plant the seed and feed it raw meat every half day and they will eventually grow. This has many uses, such as defending your house.

Watch logotzip's video on 5 bosses that minecraft needs, where it is showcased.