It wasn't what they looked like that was impressive, but what they did to survive each day and reproduce.
The shore crab (Carcinus maenas) invested 2 continuous hours to scissor open the mussel shell, only then to be mugged by three passing blennys!
In their world that is governed by energy exchanges... the crab lost some potential input, the Blennys gained an easy input and the mussel, well the mussel, just lost.
www.h2oonfilm.com (SeaShoreAntics)
salam