Treacherous Tower
The Treacherous Tower is a location present in A Link Between Worlds.
Location
The Treacherous Tower is found on Death Mountain in Lorule. It is approximately where the Tower of Hera is located in Hyrule.
Purpose
The Treacherous Tower is host to a mini game that pits Link against a room of enemies. When all enemies in the room are defeated, Link is able to carry on the the next, until he reaches the end and receives his prize. There are three modes: Beginner, Intermediate, and Advanced, each unlock by bating the mode before it.
Prizes
Whenever Link completes a round, he is rewarded with a large amount of rupees, the amount varying depending on what mode is played. Advanced, for example, gives about 5000 rupees. In addition to rupees, Link can get a Heart Piece the first time he completes the Intermediate mode. The first time Link completes Advanced mode, his Lantern is upgraded to do 8x the amount of damage. Link can then complete Advanced mode again to get the same upgrade to his Bug Net.