A ragdoll is a physics object that simulates the behavior of a limp body. Ragdolls are typically used as an alternative to death animations when a character is killed. Ragdolls are set up in your DCC tool using the PhysX plug-in, but the transition from and to a ragdoll state is handled by the animation controller. (See Install the PhysX plug-in for your DCC tool.)
Stingray supports both full and partial ragdolls (a limp arm on an otherwise mobile character). It supports transitioning both from animated to ragdoll and from ragdoll to animated. The latter can be used for an unconscious character that regains consciousness.