Undertow (CL 4)
Saga Edition Core Rulebook, page 3 (table of contents).
Underwater currents can suck swimmers down into the depths, keeping them there until it is too late.
Type: Natural
Trigger: A creature begins its turn swimming in deep water.
Attack: +6 vs. Fortitude Defense
Damage/Effect: The target is pulled 6 squares deeper underwater, and it is immobilized until the start of its next turn (Miss: The target is pulled 3 squares and is not immobilized).
Recurrence: On trigger.
Skill:
Swim (DC 16): The character can make a Swim check as a reaction to akeep from being affected by the undertow.
Special: A creature that is pulled underwater by undertow begins to drown. See the Endurance skill for information on holding your breath as well as on the effects of drowning.