diff --git a/src/p_mobj.c b/src/p_mobj.c
index 7b588645b..d433561ae 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -8627,6 +8627,9 @@ mobj_t *P_SpawnMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype_t type)
 #endif
 				mobj->subsector->sector->ceilingheight;
 
+	mobj->floorrover = NULL;
+	mobj->ceilingrover = NULL;
+
 	// Tells MobjCheckWater that the water height was not set.
 	mobj->watertop = INT32_MAX;
 
@@ -8890,6 +8893,9 @@ static precipmobj_t *P_SpawnPrecipMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype
 #endif
 				mobj->subsector->sector->ceilingheight;
 
+	mobj->floorrover = NULL;
+	mobj->ceilingrover = NULL;
+
 	mobj->z = z;
 	mobj->momz = mobjinfo[type].speed;