Rock lobster

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 rich players because of their common crimson charm drops. Using the right technique, such as ice bursting or ice barraging, killing rock lobsters is one of (if not) the fastest ways to obtain charms in RuneScape.

Obtaining crimson charms
An effective but expensive method of killing rock lobsters is using the Ancient Magicks spells Ice Burst or Ice Barrage.

Armour and weapons

 * The best magic armour the player can afford.
 * Battle robes (to save runes, combined with Staff of Light they will save 50% of runes) > Ahrim's robes/Mystic robes/Sacred clay robes/Infinity robes.
 * Arcane stream necklace > Amulet of fury/3rd age amulet > Amulet of glory > Amulet of magic
 * Staff of Light (to save runes, combined with Battle robes they will save 50% of runes)> Chaotic staff > Master wand > Ancient staff > Water staff > Chaotic staff
 * Tome of frost > Arcane spirit shield > Mages' book > Unholy book
 * Infinity boots > Wizard boots > Mystic boots
 * Gloves (barrows) > Infinity gloves >Lunar Gloves> Mystic gloves
 * God cape/Soul wars cape
 * Ring of life (for security) Seers' ring (i) > Onyx ring (i) > Dragonstone ring (i) > Beacon ring > Explorer's ring 3

Staff of light is recommended despite the lower mage bonus (in comparison to Master wand) given the fact that it gives free casts; when used in conjunction with Battle Robes, it has a 50% chance of saving runes when casting, and even when this effect doesn't activate, the Battle Robes themselves have a chance to save runes, effectively adding up to a 60% chance of saving runes.

Tome of frost is recommended above items that provide a higher magic bonus as rock lobsters have fairly low magic defence and thus the difference in offensive magic bonus is negligible, while the tome of frost saves an inventory space and the price of water runes.

Inventory

 * Death runes
 * Chaos runes
 * Water runes (not needed if bringing a water staff or Tome of Frost).
 * 50-100 Blood runes (if using Ice Barrage; also to cast Blood Burst or Blood Barrage to heal off the lobsters if necessary).
 * Proselyte armour (helm is not required), to wear while attracting the lobsters.
 * 1-2 Rocktail which heal 230 life points, or other high healing food (just in case) or Summer Pies, which restore energy and heal 220 LP.
 * Four empty spaces for charms. (Note that food and the thrownaxe are consumed getting to the rock lobsters.)
 * Rest of inventory should be filled with prayer potions, the more the better.
 * Optional: Holy Wrench to increase the amount each dose of a prayer potion will restore to save money. However carrying another prayer potion (4) instead would allow you to stay longer and might be preferred by wealthier players.

Method
Rock lobsters are found in room 16, sublevel 5, the same area where the ladder to the Dagannoth Kings is. Protection prayers are highly recommended while travelling through the dungeon to avoid damage. The room is a long corridor that stretches a bit east, and then turns and extends south-west. When the player climbs down the ladder to enter the room, the rock lobster near the ladder will attack. Protect from Melee should be activated, and then the player should run a little west to the edge of the wall and trap the lobster along the stalagmites (if this fails, run along the east side of the stalagmites, and then run back to the safespot). This is the safespot where the player will burst or barrage the lobsters. For now, the player may prepare themselves.

When the player is ready, they should put on their Proselyte armour, activate Protect from Melee, and run east to the bend and about halfway down the south west path. The player should now have seven lobsters attacking them. The player can get two more if they want, but they won't follow the player to the safespot as it is out of their wandering range. There actually is a spot where the player can burst/barrage nine lobsters at a time, but it is more dangerous and harder to get into position than the safespot near the ladder.

Now the player should run back around the bend and return west to the safespot just south of the stalagmites near the ladder. It is important that the player stands directly south of the stalagmites and next to the west wall. Walking a pace south will "untrap" the lobsters, and the player may die in a matter of seconds if they do not activate Protect from Melee in time.

The player may burst/barrage the lobsters from one of several safespots. When all are killed, they should quickly grab the charms and go back to the chosen safespot. If the rock lobster that spawns near the ladder has already spawned, the player should activate the prayer before grabbing the loot. The player may repeat this as desired. 1000 casts of Ice Burst will gain the player around 200-300 crimson charms, 100-150 gold charms, 50-75 green charms, with the amount of blue charms uncertain; with 99 magic you can do 280+ crimsons. With Ice Barrage, the accepted average is 350 crimson charms, 175 gold charms, 80 green charms, with the amount of blue charms uncertain.

Runes

 * }

Talismans

 * }

Herbs

 * }

Weaponry, armour and ammunition

 * }

Seeds

 * } tomato seed, cabbage seed

Other

 * } No lobster pot in drop table list, even though it's one of the most common drop? Same story with Soda ash. Not coins drop either (355 gp)

Trivia

 * The examine may be a reference to the B-52's song "Rock Lobster".
 * After the ring of wealth update, the charm drop rates of hellhounds and rock lobsters had "gone walkabouts". This has now been fixed.