a shit ton of watermelons

My boyfriend went out yesterday to pay his gambling debts... He came back with about 10-12 perfectly ripe watermelons. I really don't know why, I asked him and he said "don't we use stuff like that all the time" , which we do for like whipped feta arugula salads or sometimes I dice one up to make snack with but never so much at once 😂

Anyways what are some good recipes to use up watermelons? I don't want them to go bad. I was thinking maybe a pasta sauce? Any good recipes for that? What else could I do with them? Help guys.