diff --git a/src/lua_baselib.c b/src/lua_baselib.c
index 3c136a436..cfe0844ee 100644
--- a/src/lua_baselib.c
+++ b/src/lua_baselib.c
@@ -802,15 +802,12 @@ static int lib_pCheckDeathPitCollide(lua_State *L)
 
 static int lib_pCheckSolidLava(lua_State *L)
 {
-	mobj_t *mo = *((mobj_t **)luaL_checkudata(L, 1, META_MOBJ));
 	ffloor_t *rover = *((ffloor_t **)luaL_checkudata(L, 2, META_FFLOOR));
 	//HUDSAFE
 	INLEVEL
-	if (!mo)
-		return LUA_ErrInvalid(L, "mobj_t");
 	if (!rover)
 		return LUA_ErrInvalid(L, "ffloor_t");
-	lua_pushboolean(L, P_CheckSolidLava(mo, rover));
+	lua_pushboolean(L, P_CheckSolidLava(rover));
 	return 1;
 }
 
diff --git a/src/p_local.h b/src/p_local.h
index 3a0146e54..cad802910 100644
--- a/src/p_local.h
+++ b/src/p_local.h
@@ -303,7 +303,7 @@ fixed_t P_CameraCeilingZ(camera_t *mobj, sector_t *sector, sector_t *boundsec, f
 
 boolean P_InsideANonSolidFFloor(mobj_t *mobj, ffloor_t *rover);
 boolean P_CheckDeathPitCollide(mobj_t *mo);
-boolean P_CheckSolidLava(mobj_t *mo, ffloor_t *rover);
+boolean P_CheckSolidLava(ffloor_t *rover);
 void P_AdjustMobjFloorZ_FFloors(mobj_t *mo, sector_t *sector, UINT8 motype);
 
 mobj_t *P_SpawnMobjFromMobj(mobj_t *mobj, fixed_t xofs, fixed_t yofs, fixed_t zofs, mobjtype_t type);
diff --git a/src/p_map.c b/src/p_map.c
index 2d99a749e..56412a3b4 100644
--- a/src/p_map.c
+++ b/src/p_map.c
@@ -2055,7 +2055,7 @@ boolean P_CheckPosition(mobj_t *thing, fixed_t x, fixed_t y)
 				continue;
 			}
 
-			if (thing->player && (P_CheckSolidLava(thing, rover) || P_CanRunOnWater(thing->player, rover)))
+			if (thing->player && (P_CheckSolidLava(rover) || P_CanRunOnWater(thing->player, rover)))
 				;
 			else if (thing->type == MT_SKIM && (rover->flags & FF_SWIMMABLE))
 				;
@@ -3589,9 +3589,6 @@ static void P_CheckLavaWall(mobj_t *mo, sector_t *sec)
 		if (GETSECSPECIAL(rover->master->frontsector->special, 1) != 3)
 			continue;
 
-		if (!(rover->master->flags & ML_EFFECT3))
-			continue;
-
 		if (rover->master->flags & ML_BLOCKMONSTERS)
 			continue;
 
diff --git a/src/p_maputl.c b/src/p_maputl.c
index 45fc82fbf..22998c60e 100644
--- a/src/p_maputl.c
+++ b/src/p_maputl.c
@@ -662,7 +662,7 @@ void P_LineOpening(line_t *linedef, mobj_t *mobj)
 				if (!(rover->flags & FF_EXISTS))
 					continue;
 
-				if (mobj->player && (P_CheckSolidLava(mobj, rover) || P_CanRunOnWater(mobj->player, rover)))
+				if (mobj->player && (P_CheckSolidLava(rover) || P_CanRunOnWater(mobj->player, rover)))
 					;
 				else if (!((rover->flags & FF_BLOCKPLAYER && mobj->player)
 					|| (rover->flags & FF_BLOCKOTHERS && !mobj->player)))
@@ -708,7 +708,7 @@ void P_LineOpening(line_t *linedef, mobj_t *mobj)
 				if (!(rover->flags & FF_EXISTS))
 					continue;
 
-				if (mobj->player && (P_CheckSolidLava(mobj, rover) || P_CanRunOnWater(mobj->player, rover)))
+				if (mobj->player && (P_CheckSolidLava(rover) || P_CanRunOnWater(mobj->player, rover)))
 					;
 				else if (!((rover->flags & FF_BLOCKPLAYER && mobj->player)
 					|| (rover->flags & FF_BLOCKOTHERS && !mobj->player)))
diff --git a/src/p_mobj.c b/src/p_mobj.c
index ea3fd1330..15aaa6ec0 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -2222,7 +2222,7 @@ void P_AdjustMobjFloorZ_FFloors(mobj_t *mo, sector_t *sector, UINT8 motype)
 		topheight = P_GetFOFTopZ(mo, sector, rover, mo->x, mo->y, NULL);
 		bottomheight = P_GetFOFBottomZ(mo, sector, rover, mo->x, mo->y, NULL);
 
-		if (mo->player && (P_CheckSolidLava(mo, rover) || P_CanRunOnWater(mo->player, rover))) // only the player should stand on lava or run on water
+		if (mo->player && (P_CheckSolidLava(rover) || P_CanRunOnWater(mo->player, rover))) // only the player should stand on lava or run on water
 			;
 		else if (motype != 0 && rover->flags & FF_SWIMMABLE) // "scenery" only
 			continue;
@@ -2379,23 +2379,11 @@ boolean P_CheckDeathPitCollide(mobj_t *mo)
 	return false;
 }
 
-boolean P_CheckSolidLava(mobj_t *mo, ffloor_t *rover)
+boolean P_CheckSolidLava(ffloor_t *rover)
 {
-	I_Assert(mo != NULL);
-	I_Assert(!P_MobjWasRemoved(mo));
-
-	{
-		fixed_t topheight =
-	#ifdef ESLOPE
-			*rover->t_slope ? P_GetZAt(*rover->t_slope, mo->x, mo->y) :
-	#endif
-			*rover->topheight;
-
-		if (rover->flags & FF_SWIMMABLE && GETSECSPECIAL(rover->master->frontsector->special, 1) == 3
-			&& !(rover->master->flags & ML_BLOCKMONSTERS)
-			&& ((rover->master->flags & ML_EFFECT3) || mo->z-mo->momz > topheight - FixedMul(16*FRACUNIT, mo->scale)))
-				return true;
-	}
+	if (rover->flags & FF_SWIMMABLE && GETSECSPECIAL(rover->master->frontsector->special, 1) == 3
+		&& !(rover->master->flags & ML_BLOCKMONSTERS))
+			return true;
 
 	return false;
 }
diff --git a/src/p_user.c b/src/p_user.c
index 45c94827c..61492ab3e 100644
--- a/src/p_user.c
+++ b/src/p_user.c
@@ -3683,7 +3683,7 @@ static void P_DoTeeter(player_t *player)
 				bottomheight = *rover->bottomheight;
 #endif
 
-				if (P_CheckSolidLava(player->mo, rover))
+				if (P_CheckSolidLava(rover))
 					;
 				else if (!(rover->flags & FF_BLOCKPLAYER || rover->flags & FF_QUICKSAND))
 					continue; // intangible 3d floor