Cleft

Clefts are animate rock enemies resembling spiked skulls that appear in the Paper Mario series. Their name comes from the word "cleft", which can alternately refer to a crack in a rock or an indentation of the chin, both of which are characteristics of the Clefts. Clefts have a large amount of variant types, all of which are very strong and sturdy and are capable of disguising themselves as ordinary rocks, though they are also easily flipped over with an explosion or the Quake Hammer, rendering them helpless. They pursue and attack Mario by charging into him, are completely immune to fire, and aside from a few variants have spiked heads preventing him from jumping on them.

Paper Mario
In Paper Mario, Clefts are a dull brown and inhabit Mt. Rugged. When encountering one, Goombario's tattle suggests running away if the player finds them too difficult to defeat. Green Hyper Clefts inhabit Gusty Gulch and are additionally capable of charging their attacks to boost their power.

Paper Mario: The Thousand-Year Door
In Paper Mario: The Thousand-Year Door, Clefts inhabit Boggly Woods, and in fitting with its aesthetic, are monochrome. Earth Tremor does not flip them, but if executed well enough, it can defeat them automatically. Additionally, if three questions of the 65th Super Fun Quirk Quiz are answered incorrectly, the player will have to face four Clefts. Hyper Clefts also return, and several new variants of Clefts are introduced. These are the spikeless Bald Cleft and Hyper Bald Cleft, which are safe to jump on but still have high defense; the large and nigh-invulnerable Iron Cleft, which can only be defeated with Yoshi's Gulp; and the moon-dwelling Moon Cleft, which uses a brighter version of the original coloration for Cleft in Paper Mario and is said to simply be an ordinary Cleft on the moon, despite also being stronger.

Super Paper Mario
In Super Paper Mario, Bald Clefts appear in the Yold Desert region. Downtown of Crag contains a spiked, tan Cleft that is identified as a normal Cleft in the original Japanese and a Moon Cleft in the localization, despite not being on the moon. The Flopside Pit of 100 Trials contains a dark version of this Cleft called the Dark Cleft.

Names in other languages
Kirk Teschiolito