rockhopper

Short definition from Wiktionary

Noun

1. 1
   A rockhopper penguin (Eudyptes spp.).
2. 2
   Any of the order Archaeognatha of jumping bristletails.
3. 3
   A disk on the bottom of a trawler-net that lifts when it hits a rock or bump, raising the net, preventing damage to the net or the seafloor.