Rend (Ex)
Source: Advanced Player's Guide, p. 62
An eidolon learns to rip and tear the flesh of those it attacks with its claws, gaining the rend ability. Whenever the eidolon makes two successful claw attacks against the same target in 1 round, its claws latch onto the flesh and deal extra damage. This damage is equal to the damage dealt by one claw attack plus 1-1/2 times the eidolon’s Strength modifier. The eidolon must possess the claws evolution to select this evolution. The summoner must be at least 6th level before selecting this evolution.