Cloyster can only have Rapid Spin in Gen V via chain breeding, and this is how you do it.
Step 1: Get a male Squirtle (or any of its evolutions), and level it up until it knows Rapid Spin (level 19 for Squirtle, level 20 for both Wartortle and Blastoise).
Step 2: Breed with a female Kabuto or Kabutops, and the resulting offspring will have Rapid Spin. The resulting offspring you want has to be a male Kabuto, because only the male parent will pass moves down.
Step 3: Breed the male Kabuto with a female Shellder/ Cloyster and the offspring will have Rapid Spin.
Note that for both Squirtle and Kabuto, the gender percentage is 87.5% male and 12.5% female.
Cloyster moves via breeding