Sea Fright is a mighty Horde Submarine commandeered by Hordak himself. With it, he attempted to capture Unicorn Island and make it part of the Evil Horde.
The vessel came was equipped with many weapons and was even capable of moving out of the sea and onto land using tank threads to travel on land.
She-Ra, Princess of Power, destroyed the Sea Fright, forcing Hordak and Mantenna to flee in an Escape Bubble.