Temple of Koopa
From the Super Mario Wiki
The Temple of Koopa is a series of underground caverns located in Jungle Land that was said to be built by King Koopa's great-great grandkoop, which he chose to build as a place to hide the Lost Mushroom. Although Kolonel von Koop never learned about this on his own, Indiana Joe did, as he knew the location of every hidden treasure in Jungle Land. The entrance to the Temple of Koopa is shaped like a crowned Koopa's head, presumably that of its founder. The interiors consist of many boulder, mushroom and torch-filled tunnels, as well as a chamber where the Lost Mushroom was housed. At least one Fryguy and a Cobrat are known to inhabit the Temple of Koopa.
The Temple of Koopa makes its first and only appearance in The Super Mario Bros. Super Show! episode "Raiders of the Lost Mushroom". Mario, Luigi, Princess Toadstool and Toad travel to Jungle Land in search of the Lost Mushroom, and eventually encounter Indiana Joe, who, upon hearing their request to lead them to Lost Mushroom, brings them to the Temple of Koopa. Having spied on them, Kolonel von Koop and the Koopa Pack follow them to the Temple of Koopa, and opts to wait outside while the heroes recover the treasure.
Indiana Joe displays his Koopaphobia to Mario and his friends, and shows that he cannot possibly enter the Temple of Koopa, so they venture in without him. Shortly after entering the Temple of Koopa, the ceiling caves in, blocking the exit. A Fryguy soon attacks Mario's group with fireballs, and chases them through the Temple of Koopa's many tunnels. After leaping over a large Cobrat, Mario's group seals themselves inside the chamber where the Lost Mushroom is, and Mario claims it. Wanting a way out, Mario inadvertently wishes for a trap door, and the Lost Mushroom grants his request, opening up a passage underneath the group, which transports them to the Temple of Koopa's entrance. After this venture, the Temple of Koopa is never seen or referenced again.