Earth (Marvel) is an example of a character with this type of power (Fantastic Four V1 #232).
A one-shot mud creature in Uncanny Tales #53 (Atlas).
Tarmack (Dakotaverse) is a being of living asphalt (Milestone Media Universe Card Set).
Taboo (Marvel) is a monster that is also gigantic (Marvel Monsters-From the Files of Ulysses Bloodstone).
Bog Hound – TSR 2158 Monstrous Compendium Annual Volume 2
Earth Elemental – World of Warcraft Monster Guide
Excalbians – Star Trek-Who’s Who in Star Trek #1 (1987)
Living Bog – Creature Collection III. Savage Bestiary
Mudman #3 (Image)
Mud-man – TSR 2102 MC1 Monstrous Compendium
Mudman – TSR 2140A Monstrous Manual
Birdman (Hanna-Barbera) fights a monster made of earth in Future Quest Presents #5.