May I introduce you fine people to a game I became acquainted with this morning.
It is simply called 'crab'.
You replace a word in a film title with 'crab' so:
Spidercrab
The man who went up a hill and came down a crab
Top Crab
Crab Wars
Nightmare on crab st
I'm sure the hive mind of mumsnet can come up with some corkers.