// SPOILER //
The witch gives you a bag of meat as a a gift. You later give the bag to Teeth and she will be very happy with it :)
What happens if you don't beat it?
If you don't beat it you can still go see Teeth (for me I couldn't find out how to get back to the other side so I just went up) and Artemis befriends her. I'm guessing you get the same dialogue except you miss that interaction where she gets happy
