Omnd-Omnd-Ohk is a named Savage in Sir Hammerlock's Big Game Hunt DLC in Borderlands 2.
This is a highly evolved Savage, possibly a Super Ultimate Badass Warrior that has been leveled up by a Witch Doctor, possibly by a leveled up Super Badass Witch Doctor
Can transform into a powerful fire Tornado
Omnd-Omnd-Ohk spawns at the Dexiduous Summoning Station, after you have payed all the Eridium at all four Eridium Totems, but before Dexiduous the Invincible shows up, fight the Witch Doctors and let them level the Savages up until Omnd-Omnd-Ohk appears
Drops the Twister shotgun, as confirmed by a video uploaded to youtube (credit for images go to that video, see link below under "External Links"):
External Links
Borderlands 2 DLC - Dexiduous The Invincible Guide + Zapper CHOPPER Drop + Omnd-Omnd-Ohk (Video)