From this location you can look out and you might see a mermaid. There is a view of Spencer's Gulf, a well known haunt of mermaids.
The cache is a small mint tin hidden from prying eyes in a location that will make Astro sweat. Make sure you are not lured by the mermaids and wrecked. Mermaids appear in folklore as unlucky omens, both foretelling disaster and provoking it. Mermaids may speak to seamen on doomed ships telling them will never see land again.