Exo-Skull

Exo-Skull is a villain created by Dr. Animo. Exo-Skull has apparently fought Ben 10,000 before. He is a cybernetically enhanced Rhino/Human hybrid, and part of a gang of human/animal hybrids.

Alternate Timeline
In Ben 10,000, he mistook young Ben as XLR8 for his future self and attacked him, but was later easily defeated by the older Ben as XLR8.

Omniverse
He re-appeared in a cameo in Special Delivery as he was seen among the villains attending Psyphon's assembly.

Powers and Abilities
He has enhanced strength and endurance due to his large size.

He can shoot energy blasts and nets out of his horn.

Ben 10

 * Ben 10,000 (first appearance)

Ben 10: Omniverse

 * Special Delivery (first re-appearance; cameo)
 * Fight at the Museum

Trivia

 * Exo-Skull bears a heavy resemblance to The Rhino of Spider-Man. They both are somewhat Rhino/Human hybrids. They also have enhanced strength.