FusionDex

The fungus on Baysect's back is surrounded by a ring of leaves, and they exchange nutrients so that both flourish. The enticing smell of the leaves also lures in other Pokémon to have spores from the mushroom scattered on them.

Baysect are known to infest the roots of large trees en masse and drain nutrients. A Baysect's neck is ringed by curled-up leaves.