To get into its lair you have to crawl down the plant roots in the west of Falador Park, and create an instance or join an existing one. You have the option to fight the mole in hard mode, in which she will use her special attacks more frequently.
If a player is killed by the Giant mole, their gravestone will appear outside her lair in Falador Park.
The mole is level 230 and has no weaknesses, making all fighting styles equally effective ways to fight her. She spawns in the northern-most chamber of her lair, and will stay there until attacked. She will fight with standard melee attacks and no special attacks.
After her life points reach around 70,000, the current phase of the fight will end and she will dig into the ground and retreat into a random room of her lair (as long as she hasn't previously gone there), and in each room, she will have different abilities. Puffs of dirt will head in the direction of the room she went to, making them a good way to tell which room she's going to.
In each chamber of her lair she has different mechanics, which are:
In the north-western chamber, she will periodically summon Moles to aid her, which, in addition to attacking players, boost her damage reduction while present (and strength in hard mode). They are easy to defeat, only having 100 life points. If not attacked, they will die once the Mole leaves or summons new ones.
In the north-eastern chamber, she will occasionally become enraged, and will gain the ability to rapidly attack you with greater damage, but she also loses her immunity to stun. Stunning her will pacify her, in addition to lowering her defence.
In the south-eastern chamber, she will stun players and cause the ceiling to collapse, meaning players have to use freedom and move out of the way before it hits them.
In the south-western chamber, she will sometimes dig into the ground and emerge at another spot in the room, causing some rocks that damage players to appear around the spot she emerges.
In any phase, if she is unable to reach a player that is attacking her (safe-spotting or being too far from her), she is able to summon jagged rocks around them that damage them when they touch them, similar to those it summons during its digging phase.
Finally, after all previous phases have been completed she will return to the northern most chamber, and will use all of the previously mentioned abilities at once. After being killed, her drops will be distributed among all players who participated in the kill, with those who deal more damage receiving more drops. She will respawn quickly.
The Giant mole can be fought in hard mode, in which it has a number of changes to make it more difficult, although the fight is largely the same, with a key change being that her specials are more frequent and deal more damage.
Firstly, the mole will summon more mole minions to aid it, and they will also boost her strength in addition to reducing her damage received. In her digging phase, she will chain her special attack, doing it even more when more people are present. In addition, in the ceiling collapse phase, it is possible for mud to completely encase a player, in which case they may be freed by another if fought in a group, as Freedom does NOT work.
Finally, when killed, she has improved drops, including a drop exclusive to hard mode, the untradeable Ultra-growth potion, which can advance the growth of tree patches by two stages.
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The drop mechanics for the mole function differently than they do normally when fought in a group, namely, all players to contribute to kill will receive big bones, the player to deal the most damage will always receive a mole claw, the three players to deal the most damage will receive mole skins, all players with Falador elite tasks complete will receive a mole nose and all players doing the Fur 'n' Seek wishlist will receive Long, sharp claws. Finally, if a rare drop is dropped, the remaining drops will be distributed among the players who didn't receive it.
In hard mode, rare drops are more common, some items are dropped in larger quantities, and only one item is dropped at a time.
All of the mole's special drops (clingy moles, numbing roots, dragon 2h sword and ultra growth potions) are tertiary drops. Whenever someone receives a special drop from the mole, it will be announced in the game box.
The Giant Mole received a graphical and mechanical update on 27 January2014. The same update also reduced the cavern size by half. Details about the mole before her update can be found here.
Sometimes, a glitch can occur where the Giant mole may stay in one room for two phases rather than constantly moving around as her life points deplete. This only occurs when she first tunnels away to the first cavern.