Leviathan
The Leviathan based on the UH-3H variant of the famous S-61 "Sea King" helicopter that has appered on Grand Theft Auto: San Andreas. Despite it being a UH-3H, which is the US Navy cargo variant of the SH-3, the Leviathan is never found parked on near any ships, always on land. It is the second largest helicopter on the game, and has the ability to land on water. It is used on one mission with a crane attached at the bottom, that can move vehicles. Whether there is a way to obtain a regular helicopter with a magnet like this is unknown, and it is highly unlikely there ever will be. Once completing that mission a Leviathan will spawn at Verdant Meadows; your private airstrip. It is very slow and sluggish, and strangely has the same rotor sound as the Hunter, Cargobob and Raindance.