diff --git a/src/objects/shrink.c b/src/objects/shrink.c
index 7df715982..ab2cba295 100644
--- a/src/objects/shrink.c
+++ b/src/objects/shrink.c
@@ -24,17 +24,6 @@
 #include "../k_waypoint.h"
 #include "../music.h"
 
-//
-// ███████╗██╗██╗░░██╗███╗░░░███╗███████╗
-// ██╔════╝██║╚██╗██╔╝████╗░████║██╔════╝
-// █████╗░░██║░╚███╔╝░██╔████╔██║█████╗░░
-// ██╔══╝░░██║░██╔██╗░██║╚██╔╝██║██╔══╝░░
-// ██║░░░░░██║██╔╝╚██╗██║░╚═╝░██║███████╗
-// ╚═╝░░░░░╚═╝╚═╝░░╚═╝╚═╝░░░░░╚═╝╚══════╝
-//
-// FIXME (because it was completely unsearchable): vertical flip
-//
-
 #define POHBEE_HOVER (128 << FRACBITS)
 #define POHBEE_SPEED (128 << FRACBITS)
 #define POHBEE_TIME (30 * TICRATE)
@@ -135,7 +124,7 @@ static fixed_t GenericDistance(
 
 static fixed_t PohbeeWaypointZ(mobj_t *pohbee, mobj_t *dest)
 {
-	return dest->z + (pohbee_height(pohbee) + FixedMul(POHBEE_HOVER, mapobjectscale) * P_MobjFlip(dest));
+	return dest->z + (pohbee_height(pohbee) + FixedMul(POHBEE_HOVER, mapobjectscale)) * P_MobjFlip(dest);
 }
 
 static void PohbeeSpawn(mobj_t *pohbee)
@@ -303,6 +292,13 @@ static void DoGunSwing(mobj_t *gun, mobj_t *pohbee)
 		dist, FINESINE(pitch >> ANGLETOFINESHIFT)
 	);
 
+	// When in reverse gravity, flip the z offset and make up the difference in height between the Poh-Bee and its gun.
+	if (P_IsObjectFlipped(gun))
+	{
+		offsetZ *= -1;
+		offsetZ += pohbee->height - gun->height;
+	}
+
 	PohbeeMoveTo(gun, pohbee->x + offsetX, pohbee->y + offsetY, pohbee->z + offsetZ);
 }
 
@@ -311,8 +307,21 @@ static void ShrinkLaserThinker(mobj_t *pohbee, mobj_t *gun, mobj_t *laser)
 	const fixed_t gunX = gun->x + gun->momx;
 	const fixed_t gunY = gun->y + gun->momy;
 	const fixed_t gunZ = P_GetMobjFeet(gun) + gun->momz;
+	fixed_t groundZ, spriteHeight;
 
-	PohbeeMoveTo(laser, gunX, gunY, gun->floorz);
+	// Target the ceiling in reverse gravity, otherwise target the floor.
+	if (P_IsObjectFlipped(laser))
+	{
+		groundZ = gun->ceilingz - laser->height;
+		spriteHeight = gun->ceilingz - gunZ;
+	}
+	else
+	{
+		groundZ = gun->floorz;
+		spriteHeight = gunZ - gun->floorz;
+	}
+
+	PohbeeMoveTo(laser, gunX, gunY, groundZ);
 
 	if (ShrinkLaserActive(pohbee) == true)
 	{
@@ -330,7 +339,7 @@ static void ShrinkLaserThinker(mobj_t *pohbee, mobj_t *gun, mobj_t *laser)
 			laser->spritexscale = FRACUNIT;
 		}
 
-		laser->spriteyscale = FixedDiv(FixedDiv(gunZ - gun->floorz, mapobjectscale), laser->info->height);
+		laser->spriteyscale = FixedDiv(FixedDiv(spriteHeight, mapobjectscale), laser->info->height);
 
 		particle = P_SpawnMobjFromMobj(laser, 0, 0, 0, MT_SHRINK_PARTICLE);
 
@@ -383,6 +392,13 @@ static void DoGunChains(mobj_t *gun, mobj_t *pohbee)
 	fixed_t curY = gunY + (offsetY / 2);
 	fixed_t curZ = gunZ + (offsetZ / 2);
 
+	// The starting z coordinate is the bottom of the chain at the top of the gun.
+	// In reverse gravity, offset the z coordinate by the height of a chain, so that it's the top of the chain at the bottom of the gun.
+	if (P_IsObjectFlipped(gun))
+	{
+		curZ -= FixedMul(gun->scale, mobjinfo[MT_SHRINK_CHAIN].height);
+	}
+
 	chain = gun_chains(gun);
 	while (chain != NULL && P_MobjWasRemoved(chain) == false)
 	{
@@ -692,6 +708,18 @@ static void CreatePohbee(player_t *owner, waypoint_t *start, waypoint_t *end, UI
 	pohbee = P_SpawnMobjFromMobj(start->mobj, 0, 0, (baseSegs * CHAIN_SIZE * FRACUNIT) + POHBEE_HOVER * 3, MT_SHRINK_POHBEE);
 	pohbee_owner(pohbee) = owner - players;
 
+	// Flip the Poh-Bee if its target waypoint is flipped.
+	const boolean waypointflipped = P_IsObjectFlipped(end->mobj);
+	if (waypointflipped != P_IsObjectFlipped(pohbee))
+	{
+		pohbee->flags2 ^= MF2_OBJECTFLIP;
+		pohbee->eflags ^= MFE_VERTICALFLIP;
+	}
+	if (waypointflipped) // now equivalent to P_IsObjectFlipped(pohbee)
+	{
+		size += pohbee->height - end->mobj->height;
+	}
+
 	pohbee_mode(pohbee) = POHBEE_MODE_SPAWN;
 	pohbee_timer(pohbee) = POHBEE_TIME;
 	pohbee_height(pohbee) = size;
diff --git a/src/p_local.h b/src/p_local.h
index 7545c88d9..d0805b6ad 100644
--- a/src/p_local.h
+++ b/src/p_local.h
@@ -594,6 +594,7 @@ fixed_t P_GetMobjHead(const mobj_t *);
 fixed_t P_GetMobjFeet(const mobj_t *);
 fixed_t P_GetMobjGround(const mobj_t *);
 fixed_t P_GetMobjZMovement(mobj_t *mo);
+boolean P_MobjCanChangeFlip(mobj_t *mobj);
 
 void P_InitTIDHash(void);
 void P_SetThingTID(mobj_t *mo, mtag_t tid);
diff --git a/src/p_mobj.c b/src/p_mobj.c
index 732dabcf5..a2aa2f977 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -1116,7 +1116,7 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 
 			gravityadd = -FixedMul(gravity, gravfactor);
 
-			if ((rover->master->frontsector->flags & MSF_GRAVITYFLIP) && gravityadd > 0)
+			if ((rover->master->frontsector->flags & MSF_GRAVITYFLIP) && gravityadd > 0 && P_MobjCanChangeFlip(mo))
 				mo->eflags |= MFE_VERTICALFLIP;
 
 			no3dfloorgrav = false;
@@ -1128,7 +1128,7 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 	{
 		gravityadd = -FixedMul(gravity, P_GetSectorGravityFactor(mo->subsector->sector));
 
-		if ((mo->subsector->sector->flags & MSF_GRAVITYFLIP) && gravityadd > 0)
+		if ((mo->subsector->sector->flags & MSF_GRAVITYFLIP) && gravityadd > 0 && P_MobjCanChangeFlip(mo))
 			mo->eflags |= MFE_VERTICALFLIP;
 	}
 
@@ -14980,6 +14980,25 @@ fixed_t P_GetMobjZMovement(mobj_t *mo)
 	return P_ReturnThrustY(mo, slope->zangle, P_ReturnThrustX(mo, angDiff, speed));
 }
 
+// Returns whether this mobj is affected by gravflip sector effects.
+boolean P_MobjCanChangeFlip(mobj_t *mobj)
+{
+	switch (mobj->type)
+	{
+		case MT_SHRINK_POHBEE:
+		case MT_SHRINK_GUN:
+		case MT_SHRINK_CHAIN:
+		case MT_SHRINK_LASER:
+		case MT_SHRINK_PARTICLE:
+			return false;
+
+		default:
+			break;
+	}
+
+	return true;
+}
+
 //
 // Thing IDs / tags
 //
diff --git a/src/p_spec.c b/src/p_spec.c
index 774811b99..68356d7ca 100644
--- a/src/p_spec.c
+++ b/src/p_spec.c
@@ -3293,7 +3293,7 @@ boolean P_ProcessSpecial(activator_t *activator, INT16 special, INT32 *args, cha
 			break;
 
 		case 433: // Flip/flop gravity. Works on pushables, too!
-			if (!mo)
+			if (!mo || !P_MobjCanChangeFlip(mo))
 				return false;
 
 			if (args[0])