This is a very good story that with a little tweaking could be a great story. First of all, it's funny. It's a scary story that manages to be funny. It also humanizes the characters. The beginning, when we meet Mr. McKoy, warms us to his character. It's a great start and sets the dynamic between the adult and the children (teenagers).
The story line is good too. The witch introduction kind of pokes fun at trite stories that have scary witches kidnapping children. You break the mold. And 'Mr. Green' is delightful, especially the fact that you choose to end the story with him.
The weak points occur during the fight scene, where it is difficult to follow the action at times. That would be easy to edit.
You do a good job in response to the prompt, @gabmr. Thank you for sharing this story with us.
Writing about a number of characters and details that resembled old summer days was a pleasure for me.
Thanks @theinkwell for the enriching comment and inspiring prompt🙂