Nihilego

Like any other Pokémon, Nihilego is truly a benign creature, and the Pokédex entry brings up the fact that they are possibly non-sentient. Like other Ultra Beasts, Nihilego, while in the normal world would become panicked and will start attacking people affected by Ultra Wormholes in an attempt to return to their home but they have a unique trait that makes them one of the most dangerous types of Ultra Beasts; their venom, which decreases inhibition of their victims while drawing out their latent power. The ultimate goal of this is to drive hosts into attacking and destroying any potential threats to the Nihilego. When Lusamine was constantly affected by Nihilego venom, her preexisting obsession with the Ultra Beasts became outright hostile to anyone who may threaten them and amplified her negative qualities into borderline sociopathy. Nihilego do not directly control their hosts, however. It sometimes behaves

Nihilego is an Ultra Beast that resembles a jellyfish. The bell is semi-translucent and encircled with several white, star-shaped markings. The wavy rim of the bell flares outward and is bright blue. Somehow she still has fat tits like a young girl, but it is not known why it does so.