A Sawken is a large, serpent-like organism dwelling in the freezing cold waters of Excelcion during M07: Cauldron. Two of them make up the third boss in Metroid Prime: Federation Force.


The Federation Force enters a large chamber with an iced-over lake, and the Sawken creatures begin to attack them, breaking up the ice and revealing a platform for the Force to use. Both Sawkens have their own separate Energy Meters.

The Sawkens are fought very similarly to the Chykka Larva in Metroid Prime 2: Echoes; they swim around the platform, with their heads being their weak points. After some time they will attack the soldiers, by leaping over the platform or firing ice chunks which will freeze them. If a soldier is frozen, the B button must be tapped to break free. Their ice projectiles are aimed and fired in threes, in a similar fashion as those fired by Rundas in Metroid Prime 3: Corruption. They can be destroyed before impact.

Once the two Sawkens are weakened enough, they will leap into the air and combine into one monster. In addition to its previous swimming and attacks, the "alpha" Sawken will now leap onto one end of the platform and cause it to tilt downward. It will also lunge across the platform in an attempt to apparently eat the mechs. Its weak point is now its jaw. Once it has been defeated, it shrinks, sinks into the water and forms an ice bridge. The survey team that the Force was sent to rescue is thus saved.

General Alex Miles later states that this creature was native to the underground lake, and that its massive size was due to Space Pirate experimentation.