Scratch's summon spell disappears after completing the post quest in Act III. I completed the quest favorably; the woman left, the halfling was happy and freed all the dogs from their cages, but the button for the spell was instantly removed and I can't get it back. Scratch IS still in camp.
Others that have reported it said they were able to get the spell back by using "his" ball but I have never been able to get any of the balls to work with Scratch (can't fetch, no achievement).
