Seedling

The sapling walks behind you on two little roots and only breaks character when you get too far ahead. Then it sprouts leaves off its arms, flaps them, and glides over to catch up. It does the same thing if you are hovering above it. Watching it commit to flight is most of the charm.

Plantera has a short list of dedicated drops and this is one of them, so a single kill rarely produces it. That matters less than it sounds. Bulbs keep growing back in the jungle for the life of the world, and by the time you have farmed her enough for the Temple key and the weapons you wanted, the pet has usually turned up on its own.