It is a big robot built entirely by sand. Its shown to wear armor, and has two big claws instead of hands. It has a "P" in the center and Patrick controls it from the top.
Patrick owns it. Its enemy is SpongeBob's Sand Tank and was only shown in Sand Castles in the Sand. It was made by Patrick to try and kill SpongeBob. SpongeBob made a tank to destroy Patrick. This robot was made for the alternate purpose of winning The Sponge/Star Sand War.