Cloyster's not a bad anti-lead in DPP, though. It has good physical bulk, sets up Spikes, and can take down most suicide leads with Surf, using Ice Shard to finish off Sash mons. It can also go suicide itself with Explosion, or Rapid Spin to get rid of SR after the suicide lead is dead. It's certainly not the best lead around, but it's not a bad choice if you wanna set up Spikes while screwing over certain other leads.
Down in UU, it's got some good versatility as both an offensive Spiker/spinner and a bulky utility mon. Skill Link Rock Blast is also pretty cool for breaking through Subs and Sashes, and it's more powerful than Stone Edge :3