Infinite Tunnel (5e Trap)
From D&D Wiki
This long hallway contains a seamless blend of arcane runes and mechanical treadmills, which give creatures attempting to traverse it the impression that it is an infinitely long hallway. Most infinite tunnels are placed on stairs and slopes so they are harder to notice. A creature can sense that the infinite tunnel is a deception with a successful DC(19) Perception check or by use of the detect magic spell.
This trap inhabits a hallway no wider than 10ft and no taller than 15ft. When a creature completely crosses the trap's area of effect by non-magical means, they are teleported to the beginning of the trap's area of effect in such a way that the creature is unable to tell they were moved. The trap can be disrupted by casting dispel magic on it or by succeeding on a DC(20) Sleight of Hand check, clearing the trap's effect for one minute.