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 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.

Be aware that if you die, do not expect to have your gravestone blessed or repaired as there is currently a glitch causing the message: "You cannot bless this gravestone at this point." or "You cannot repair this gravestone at this point." when either trying to bless or repair a gravestone at any point - even at 1 second remaining.

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. Note: Another useful tactic (they have a low magic defence) is to use (Elite) Void knight equiment, preferably with a Deflector and a good mage robe top.
 * Head: Virtus > Healer hat > Battle* > other Magic headgear (like the Farseer helm) or a Helm of neitiznot
 * Top: Virtus > Ahrim's > Infinity > Dagon'hai > Sacred clay > Battle* > Mystic
 * Bottom: Virtus > Ahrim's > Infinity > Dagon'hai > Sacred clay > Battle* > Mystic
 * Neck: Amulet of Fury > God Stole >Amulet of Glory > Arcane Stream Necklace
 * Staff: Staff of Light*> Chaotic > Polypore staff > Master wand > Ancient > Water/Mud (for bursting and Lunar teleports)
 * Shield: Arcane spirit >Tome of frost> Farseer Kiteshield > Mages' book > God book (Unholy > Ancient > Balance) > Broodoo
 * Boots:Ragefire > Infinity > Wizard's > Mystic
 * Gloves: Spellcaster gloves > Barrows > Infinity > Lunar > Regen bracelet
 * Cape: God/Soul wars > Ardougne
 * Ring: Ring of life (for security) or Ring of Wealth or Imbued Rings > Explorer's 3/4 > Beacon
 * Aura: Reverence (best to also use a Holy Wrench) > Runic Accuracy


 * These should be combined with each-other, as they will save 50% of all runes (used in Combat spells), and on top of that 15 to 20% chance to save Catalytic runes.

The Arcane Stream necklace is not as important here as the magic damage boost it adds only applies to the target you click on. The other 8 targets do not receive the damage boost from it or your staff, so you would be better of using a necklace with a prayer bonus.

Staff of light is recommended despite the lower mage bonus (in comparison to Master wand, or Chaotic staff) 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. The Battle robes will, however, only last for 6 hours of combat / afterwhich they will need to be recharged (275 tokens).

Provided you are going to be bursting a Tome of frost is recommended above items that provide a higher magic bonus. This is because rock lobsters have fairly low magic defence (thus the difference in offensive magic bonus is negligible), while the tome saves an inventory space and the need/price of Water runes.

Inventory
Note: In order to save inventory space, it might be better take into account their low magic defence. If not using the Battle robes or (Elite) Void, leave behind a mage headgear and wear the Neitiznot Helm. Also use the Reverence aura paired with a Holy Wrench, this greatly increased the amount of prayer points being restored and could save some food.
 * Overload/Extreme magic/Magic potions/Vecna Skull or flasks
 * Prayer renewal potions to lessen prayer point loss
 * Death runes
 * Chaos runes if using Ice Burst
 * Water runes (or a Mud/Water staff/Tome of Frost).
 * Blood runes (if using Ice Barrage; also to cast Blood Burst or Blood Barrage to heal off the lobsters if necessary).
 * Soul runes for healing using Blood Barrage
 * Enhanced excalibur for healing, if needed. Can be replaced with a Saradomin brew
 * Place holders for charms.
 * Prayer potions/Super prayer potions, as many as needed for your trip.
 * Optional: Summoning Familiar

Method
Rock lobsters are found on Waterbirth Island, 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 you climb down the ladder to enter the room, the rock lobster near the ladder will attack. Protect from Melee should be activated, and then you 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 you will burst or barrage the lobsters.

When you're ready, you should put on your Proselyte armour, activate Protect from Melee, and run east to the bend and about halfway down the south west path. You should now have seven lobsters attacking you. You can get two more if you want, but it involves running past the Wallasalki and Ranged Dagganoths. There is another spot where you can burst/barrage nine lobsters at a time, but it is more dangerous and harder to get into the position than the safespot near the ladder.

Now you should run back around the bend and return west to the safespot just south of the ladder. It is important you stand directly south of the ladder. Walking a pace east will allow the lobsters to attack, and you may die in a matter of seconds if you do not activate Protect from Melee in time.

You may burst/barrage the lobsters from one of several safespots. When all are killed, you can grab the charms as this is a safespot from respawns. If the rock lobster that spawns near the ladder has already spawned before the original 9 lured lobsters are dead, you should activate the prayer before killing the rest of the lobsters. You 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

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Talismans

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Herbs

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Equipment

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Seeds

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Other

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Trivia

 * The examine is likely 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.
 * The rock lobster's combat level was changed from 127 to 156 in February 2011.