The Key

The Key is one of 201 treasures in Pikmin 2. In order to obtain it, go to Sublevel 5 in the Citadel of Spiders located in Perplexing Pool. Use your yellows to defeat the Beady Long Legs and get The Key, worth 100 Pokos. It unlocks challenge mode. In challenge mode, you must find the key on each sublevel to open up holes and eventually escape the challenge.