Rock lobsters are found in the Waterbirth Island Dungeon's fifth sub-level, in room 16. They are similar to Giant Rock Crabs in the fact that they are initially disguised as large rocks, but they will attack the player as they approach. They have very high defence (though they are weak to magic attacks) and can hit up to 150 life points, but rarely hit over 110 life points. Their attack speed is two bars faster than the Abyssal whip's (as fast as darts on rapid fire), making them incredibly dangerous. Rock lobsters are commonly killed by wealthy players because of their common crimson charm drops. However with the use of charged battle robes, a reward from the Fist of Guthix minigame, the price is significantly decreased. Using the right technique, such as ice bursting or ice barraging, killing rock lobsters is one of (if not) the fastest way(s) to obtain charms in RuneScape.