What does Costa want from me?

Hint 1 of 8:

A trade for something valuable.

Hint 2 of 8:

How about for an artifact, maybe from Atlantis?

Hint 3 of 8:

Someone you've probably seen was trying to get an artifact, but wasn't
having too much luck.

Hint 4 of 8:

Professor Heimdall in Iceland was trying to get something out of the ice.

Hint 5 of 8:

The sculpture has an open mouth.  You might want to put a "key" in there,