Psyglip

The diminutive Myconid Sprout named Psyglip was rescued from a chunk of driftwood floating across the Cackling Deep.
They are endlessly curious, and they love you. If anything bad were to happen to you, they would kill themselves.
Psyglip, when they were just a spore, somehow drifted away from their colony and found purchase on a log, where they sprouted. They don't know exactly where the rest of his colony is, but knows the general direction.
They have a biological want to return to their colony, but are also more than content to accompany the party on their adventures.