Subterranean temple

A Subterranean Temple appears in the 1987 cartoon episode Splinter No More.

Back in the 1920's, a cult used the temple to open portals. When Shredder learns of it, he tries to do the same thing. However, he accidentally opens a portal to wrong place, causing an extraterrestrial tentacle monster to appear on Earth. To get rid of the monster, Shredder has to team up with the Ninja Turtles and trick the monster into destroying the entire temple.