The Black and White Nightmares are demonic monsters that have escaped from the Black and White Universe and are now working for Mok. You will see them in the finale of Non Disney Heroes vs Villains. Some resemble modern day animals, but don’t be fooled. These things are evil.
Non Disney Heroes Vs Villains War
It was the evil legions of the Triumvirate of Terror, being the creations of Bendy and Skitzo the Bear, who helped their evil masters make hell on the cartoon island, until King Morpheus intervened to send the Devil, Skitzo and Bendy back to hell, but his legions remained tormented for a long time on the island.