Minicula

From the Super Mario Wiki

Miniculas are enemies in the game Wario Land 4. Miniculas can't be defeated by Wario. The Miniculas are the only creatures in Wario Land 4 that can turn Wario into Vampire Wario. Miniculas appear in only two levels in the Sapphire Passage, these levels are Crescent Moon Village and Hotel Horror. Miniculas aren't aggressive towards Wario. They try to avoid light.