A stargazer of some sort. Where you found it is always helpful, as is size.
Just saw some other posts, It must be what one guy says, it's a Lophius piscatorius. Here is a copy of what another posted:
Definitely a monkfish, also known as a goosefish here in New England. They are quite plentiful and buttf*$@ing ugly. Huge mouths. A football will fit sideways in their heavily toothed mouth. Rows of teeth that curve backwards. They get pretty big, 3 feet or more. Not very good swimmers. Remind me of chickens, they swim up and drop back down to the bottom. Some of the dives we did off Chatham, Mass. had so many of them on the sea floor you didn’t dare set your foot down. Nothing worse than seeing one at night