This witch bunting costume looks like it could work for a baby boy's costume too. I guess technically boy witches are called warlocks. Anyway, it's a no-frills costume that would keep Baby warm during your Halloween evening adventures. It's also available on Amazon.
A spray of roses on this infant witch costume softens the horror theme a little bit - unfortunately. If you can even get your baby to leave her hat on! This baby witch costume is also found on Amazon.