Where is the Great Seal?

Hint 1 of 6:

You'll need to wait a while before you have the items you need to get it.

Hint 2 of 6:

In fact, wait until after the Tanning contest.

Hint 3 of 6:

The seal is in that trunk at the bottom of the cliff.

Hint 4 of 6:

See the question about scaring away the jellyfish to open it.

Hint 5 of 6:

You also need to find an item to get the seal.

Hint 6 of 6:

It just happened to appear when you left the lighthouse.