Sea Monster Pirate Set is an Adventures set. It features a pirate ship which the included ocean covered Thomas can go inside. Rocking the ship which has been captured by the sea monster back and forth can move Thomas up to the top where activates a feature which drops a treasure chest out as well as make the sea monster's mouth close. Then he can safely escape with the chest out the other side of the ship. Engines can also hang off the tentacles of the sea monster.
Illustrations of Diesel as a pirate, Iron 'Arry, and Iron Bert appear on the set. Diesel's face also appears on the flag as part of the Jolly Roger.