A_ForceStop is an action that immediately stops the actor's movement in all (or some) directions when used. Var1 determines whether vertical momentum is stopped or not – if Var1 is 0, both horizontal and vertical momentum are stopped; otherwise, only horizontal momentum is stopped.
This action originates from the v2.0 modification SRB2Morphed and was added to SRB2 itself in v2.1.
Code – A_ForceStop
// Function: A_ForceStop
// Description: Actor immediately stops its current movement.
// if var1 == 0, stop x-y-z-movement
// else, stop x-y-movement only
// var2 = unused
void A_ForceStop(mobj_t *actor)
INT32 locvar1 = var1;
if (LUA_CallAction("A_ForceStop", actor))
actor->momx = actor->momy = 0;
if (locvar1 == 0)
actor->momz = 0;