Hm... this reminds me of the mermaid in Zelda; Link's awakening, where one of the "trade-items" is a top you have to get back to the mermaid. Interresting little fact... on the German version I played (and it turns out it was on European pre-DX and Japanese versions), it was a bikini-top. In the English version a necklace. Prudes. When you dive down to look for the top she dives away and sais so'm like "Don't look!". With the necklace, "I've already looked there".