When a character is killed by an explosion fatality or something similar, they have a regular human skeleton. Even if it was a four-armed character, reptilian, or cybernetic ones. Likewise, sometimes the number of skulls on the ground following such a fatality is often inconsistent.
When a character is decapitated in a fatality, their lifeless body remains standing upright.
Ermac appears here with white skin. In Ultimate Mortal Kombat 3, he had black skin.