Teufelstisch, Rock formation in Lake Constance, Germany.

The Teufelstisch is a rock formation in Lake Constance with a flat plateau measuring roughly 22 by 10 meters. This plateau normally sits about 1.5 meters below the water surface and features steep walls that drop away sharply on all sides.

Diving at the Teufelstisch was restricted after fatal accidents in 1977 (four deaths), 1979 (two), 1991 (one) and 1993 (two), and was banned outright in 1994. Only experienced divers with an exceptional permit may still dive there; a further death was recorded in April 2011 at 61 metres.

This rock formation serves as a navigation marker for boats crossing Lake Constance and carries the reference number 22 on nautical charts. Locals and sailors recognize it as part of the lake's natural landmarks that guide daily water traffic.

From the shore, the rock is visible from the Bodensee-Rundweg between Wallhausen and the Marienschlucht, about one kilometre northwest of Wallhausen, on the right; look for the back of marker 22 and the pale water over the elliptical shallows. The plateau lies 50 metres from the bank and only breaks the surface at very low water, below 2.30 metres.

The rock is not fully detached: a narrow rock bridge called the Sattel links it to the Bodanrück base at a depth of about 32 metres, so only slightly more than 30 metres of the pinnacle stand free. The plateau, roughly 22 by 10 metres, has broken the surface only in reported low-water years such as 1823, 1949, 1963, 1972 and 2006.