The Slumbergath is a creature of the night and a complex of nightmares of mulitple people. Origined from the television series, "Aladdin", specifically in the episode, "When the City Snoozes", the Slumbergath can change it's form to various creatures. The Slumbergath appears briefly in the second part of Disney vs. Non-Disney Villains War.
Disney Vs Non-Disney Villains War - Part Two
Mirage summons the Slumbergath to deal with one of Skeletor's warriors, Evil Lyn. The beast takes the form of dragon, ready to take out the sorceress with his flaming breath. However, it is no match against the Evil Lyn's powers, who disposes off the creature, much to Mirage's fury.