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The Square Key (Japanese: しかくのカギ) is an item in Densetsu no Starfy 2. It is found in Lobber's Cave (Stage 1-4). It is found past a door that requires the Triangle Key to open. The Square Key is one of three keys required to remove the three different types of keyholes found in the area and get to the boss battle with Konk and Puchi Ogura #1. The other two are the Circle Key and the Triangle Key. The Square Key removes the only green square keyhole.