Rock Crabs are aggressive monsters that look like harmless rocks while they are disguised, but when unsuspecting passers walk by, they attack; however, once their target leaves the nearby area, they are no longer aggressive. It should be noted that, unlike most other enemies and NPCs, rock crabs are not marked with yellow dots on the minimap; this is probably due to the fact that the crabs' appearance camouflages them as rocks. Players can tell if a rock is a crab or not by looking at the rock's shape, Rock crabs are tall oval shaped, but normal rocks in their area are mostly in large clusters of shattered pieces. It should also be noted that, as with most aggressive monsters, rock crabs will stop attacking a player if they have not left the surrounding area in a considerable amount of time (roughly between ten and twenty-five minutes). To fix this, simply run out of the surrounding area (to be sure, run halfway to the entrance to the village of Rellekka or simply enter and exit the entrance to Keldagrim) and run back, at which point the rock crabs will once more be aggressive. As they are "dormant" until "awoken" by a passing player, rock crabs cannot be attacked until they are made aggressive once more.
In the quest Fur 'n' Seek, its carcass must be collected and cleaned for the Odd Old Man.
For low defence levelled players, it is recommended that if you are killing these creatures for long periods of time, you bring some food just in case as there are no nearby banks. It is also recommended that you bring a Camelot teleport/teletab to bank for more food as it is near the area of the rock crabs, or home teleport to Seers' Village. You could also use the bank in Keldagrim. The entrance is right between the statues to the east of the Rock Crabs.
Rock Crabs used to be commonly trained upon due to their high exp rewards; and occasional valuable drops, low combat level and defence. Most places where Rock Crabs reside used to be heavily crowded. After the Evolution of Combat update, Rock Crabs became level 102, making low-level training very difficult. After the Legacy Combat update, their combat level was altered to 71.
Universal dropsThese drops are dropped alongside main drops.
These animals are most likely, as the name suggests, a form of crab, noting that the rock crabs always walk sideways (and attack by smashing their sides into the player). It is possible that they may belong to a different animal phylum, such as insects, and only look like crabs, although this is not very likely. The animals are always spotted near water; while the graphics of RuneScape do not show them immersing themselves in water, it can be safely assumed that they would hypothetically do so. In the quest Fur n' Seek, the rock crab's carcass that is collected by the player consists of only a shell and other, not easily visible remnants.
- The examine for rock crabs is: "No-one likes crabs..." This could be a reference to grumpy people, as they are sometimes called "crabs".
- If a rock crab is killed in a small ditch a glitch will happen where the drop will be floating.
- Rock crabs seem to be one of the earlier species of Gielinor being observed in the Second Age by Armadyl in his travels.[source needed]