10 Most Powerful Horror Movie Villains

In Wishmaster, Alexandra Amberson summons a genie called The Djinn, who is obligated to grant the wishes of anyone who approaches him. 

However, the wicked warlock distorts every wish, often with deadly consequences. A woman wishes to be beautiful forever, causing her to be turned her into a mannequin. When a person desires to be thinner in Wishmaster 3, The Djinn makes her vomit up her insides.

Although The Djinn initially comes across as a mere trickster, his power is basically unlimited since he can warp all of reality or turn back time in a heartbeat. He's impervious to harm and cannot be destroyed, so the only way to defeat him is to wish him away.

Unfortunately, this is easier said than done. Wishing the Djinn to disappear could cause the entire world to disappear along with him. If you wish you never met the titular fiend, he could make it so you were never born. As a result, you need to wish for The Djinn to vanish in an extremely specific way to avoid it massively backfiring. 

But since The Djinn is immortal, it's only a matter of time before he's summoned again and his reign of terror continues.