How to Make a Poseidon Costume. Poseidon, the Greek god of the sea, earthquakes and horses, is a very important god in Greek Mythology. He is the father of many other gods and goddesses, including Theseus, Pelias and Neleus. For your next costume party, look like you've just stepped (or swam) out of your ocean kingdom.
Things You'll Need
Light green fabric
Do not use real sea animals on the Poseidon costume, or one will really smell like the God of the Sea.