GOTO-9 is the third miniboss you encounter, a strange Crab/Spider like creature that loves mushrooms.
Like his predecessors, he suffers poor vision and hearing, and will blindly eat things, including but not limited to mushrooms that you drop, dead fighters, and you.
Leave GOTO-9's Aura Alone!
"GOTO-9 has some nasty attacks, with its slippery vomit and stuff. Its body press is especially painful. Run and jump to evade it, and don't get close when its aura emerges. How to attack? Well, it likes mushrooms, so try throwing some!"
11F MAKA-TSUTSUMI -- GOTO-9
When GOTO-9 has its red aura, throwing a crushroom will cause it to eat it, and then run headfirst into a wall, giving you time to attack it freely. Make sure to follow up and attack, as eating things you throw also allows GOTO-9 to heal a bit.