Ugudenk, The Squirming King (Patreon)

Referred to as the Squirming King, Ugudenk was a worm-like Obyrith that primarily dug through  his Writhing Realm. Seemingly immortal, it was speculated he was himself an Abyssal layer, his  maw a feeding tendril that sometimes reached across the multiverse to devour at apparent random.  His presence brought a fear of that which burrowed, and the crippling thought he could burst from  the ground at any time. Ugudenk had the form of an impossibly large worm-like creature; in fact, no one could claim to have  seen the end of its body. Its jaw was a complex structure of multiple jaws and hooked tentacles  made of muscle, the whole of which opened like some horrifying carnivorous flower when it hungered

Art by Marion Bouzor on Artstation