Shark's Lair (often abbreviated "sl" by players) is a multiplayer instance, meaning that 2-5 players may participate in it at once to defeat the two larger shark brothers.
Battle Shark Bosses Glacius and Pyros, and be awarded with EXP, Silver and Prestige. Don't let them get close, or they'll restore each other's HP.
There are three levels: Normal (easy), Heroic (medium) and Nightmare (hard). You can do each type of instance twice per day.
To initiate Shark's Lair, the leader of the party must open the "Multiplayer Instance" (MI) panel, sign up the party and enter.
The Lair itself looks a little like Icy Impass. You can jump onto the chains to rest and recover your HP if needed.
The two sharks tend to have higher defence or health and produces more heavier damage (attack power) on the players in Heroic and Nightmare modes. The higher the level of the sharks (the average of the levels of the players in the party), the more difficult it is to defeat it. The red shark, Pyro, is also supposedly harder to defeat then the blue one, Glacius.
The sharks' health, HP, may also regenerate if it is drained very slowly due to the players having difficulty to do much damage. If one shark is defeated and the other is not defeated quickly enough, the defeated one will regenerate at full HP.
Separating the sharks then separating the party in half to defeat the sharks simultaneously is a common tactic, especially for lower levels, as it somewhat decreases the difficulty.
You also have a time limit of 30 minutes, but most people complete the instance before that.
You can gain a number of awards from this instance. At the end of each instance you automatically get some silver and prestige.
Normal: 100k silver + 500 prestige
Heroic: 200k silver + 1k prestige
Nightmare: 300k silver + 2k prestige
There is also a treasure chest that you can open after completing the instance. This always contains a 50k Silver Card, which you can click to gain an additional 50k silver per day. Usually you get 14 of these 50k Silver Cards if all three types are completed twice. Sometimes, you can also get 1-4 Aerolite and/or Siderite Stones in these chests.
The EXP gain depends on the average level of the party (= the level of the sharks) but is usually not very much.
You can gain 10 achievement points for completing Shark Lair (Heroic), 10 times. This is the equivalent to 500 max HP and 50 vouchers. In other words, might will also increase.