Combine any movie with a bad movie and feel free to add a synopsis for your creation. I'll start with:
Jaws: The Revenge of the Creature ~ Chief Brody's widow believes that her family is deliberately being targeted by another shark in search of revenge. In desperation she frees a captured creature from the Black Lagoon and makes him hunt the shark.
Stand by Mac and Me ~ After the death of a friend, a wheelchair-bound writer recounts a boyhood journey to find an alien escaped from NASA.
The Perfect Perfect Storm ~ A female aerobics instructor meets a male reporter on a fishing vessel doing a story on intense storm patterns, but it isn't love at first sight.
Manos: The Hands of Steel and Fate ~ A family gets lost on the road and stumbles upon a hidden, underground, devil-worshiping cult led by a cyborg programmed to kill a scientist who holds the fate of mankind in his hands.
I'd have given you karma for this brilliant idea.
Have a gold star instead.