Dark Bristle

From the Super Mario Wiki

Paper Mario: The Thousand-Year Door Enemy
Dark Bristle

Max HP	8
Attack	8
Defense	4
Location(s)	Pit of 100 Trials (Floors 81-89)
Log	An ancient creature made of rock. Its Defense is high. You can't jump on it because of its spikes, and you can't get close to it because of its spears.
Items	Super Shroom
Moves	Destruction (8)
Tattle	That's a Dark Bristle. It's an ancient creature made of rock. You can't Jump on it because of its spikes, and you can't approach due to its spears. AND its Defense is high. You'd better take it out with special attacks or items.
Bestiary 84 85 86

The Dark Bristle is a more powerful version of the Bristle fought in Paper Mario: The Thousand-Year Door. Dark Bristles are only found in the Pit of 100 Trials, on levels 81-89.

The Quake Hammer badge is incredibly useful against these enemies. It will flip them over for two turns, dropping their Defense to 0 and making them utterly useless. Also, if Mario is wearing the Spike Shield badge, they will not extend their spears to poke him if he readies his hammer. Being stomped with Spike Stomp also works, as does the Star Power Earth Tremor.