After running aground, the PC's see a tower through the mist.
Through the mist, they see a tower on an a craggy jungle island near by. The captain swears this island was not on any of his charts, and that he's plied these waters many times and has never seen it before.
There is one working small boat they can use to row to the island to try to get help.
Though they can not see anything they can hear sounds in the distance of what they have no idea but it sounds terrifying to say the least. The tower itself looks ominous in the distance with its vines and growth so thick you can not make out what the tower is made of. The only thing they can see is the light from one window that shines like a beacon whether its a warning of danger or not is what they must decide.
They have washed up on a small beach of red warm looking sand not far from the the overgrowth beyond they have two routes follow the beach around in hopes they can make it to the tower or wade through the jungle beyond which seems to have a small path. The path is well worn from what he PCs can see but the mist is heavy so visibility is lower than they would like.
If they take the beach they could get warnings or help from perhaps sea elves that live near the island. If they take the jungle path I would set up some traps designed to scare visitors away with them eventually becoming traps that are designed to capture those that did not take the warning. Now what would a wizard what live subjects for is the question....