The King of Lakes

The Lungfish is a huge amphibious fish-like creature found in the largest lake in the 22nd Floor of Aincrad that classify as King of the Lake. It can only be encountered by using a special bait and have enough mastery of fishing skill. It has the ability to swim and walk on land.

Sword Art Online
Nishida, a well known professionally skilled fisherman requested Kirito to help in catching the fish as he has the fishing skills to catch it but lacks the strength to pull the creature out of the water. Nishida got the fish and then switched with Kirito. Kirito managed to lure the thing out of the water but it turned out to be enormous. It start chasing Kirito, but was then killed by Asuna using her high level sword skill.