The temple has a stone door with a stone frame and a large stone slab on the ground in front of it.
The stone slab turns to mud if the door is attempted to be opened.
The door is locked and requires a DC 14 Dexterity check with thieves’ tools to open, or a DC 18 Strength check to force open. However, when unlocked or forced open, the stone slab at the entrance turns into soft mud.
Any target that starts their turn or enters the area must make a DC 8 Strength check to move. Movement is a 1/4 speed.
One round later, the mud turns back to stone. Those in the mud must make a DC 14 Dexterity check at disadvantage. On a success, they may attempt to leave the mud, which requires the Strength check. Otherwise, they become stuck in the stone.
While stuck in the stone they are restrained.
A trapped target can escape by breaking the stone. In order to break the stone, it can be attacked. It is AC 18 and 50 hp.
Any type of dimensional travel, such as teleport can be used.
Or, after 1 hour, the temple door can be re-opened, which will turn the stone to mud again.
A detect magic detecs an aura of transmutation on the door.
A dispel magic (DC 15) disables the transmutation effect, but does not free any trapped targets.