Curse of Gibbering

When you cast this spell, the target must make a Charisma check. If it fails, the target has disadvantage on all Charisma saving throws. When it fails three, a Gibbering Mouther appears, and then you roll a d6. On an odd number, the gibbering mouther attacks. On an even number, it will protect the target, and when something attacks the target, the gibbering mouther has advantage on a roll that is attempting to attack it for 1 minute. In any coincidence, when the Gibbering mouther dies, it can make a Arcana (Intelligence) check (DC18). If it succeeds, it becomes a zombie under the target's control. Once that dies, the target's alignment becomes Chaotic Evil. If you dispell it at any time, all effects/creatures disappear/wear off.