Rising from the depths to wreak havoc on mankind, the Seaweed Monster grew at an alarming rate. Highly energized by radiation, the fiend quickly attacked Brock and Quinn went they went diving. Fortunately for the pair, Godzooky managed to rescue them, but the creature wasn't far behind. It attacked the Calico, but Godzilla was called quickly to help.
Godzilla rose from the ocean to do battle with the Seaweed Monster. In the end, the Seaweed Monster was forced to retreat. Pieces of the creature aboard the Calico began to mutate and form new monsters while the larger one headed directly for the coastline.
The Calico managed to dump the two smaller beasts, but they simply joined with the bigger one. Godzilla was again called in and as they fought, Quinn discovered that the seaweed dried up and died when exposed to the sun. Now knowing this, Godzilla hoisted the creature onto his back and began to head for land. The sun began to dry the Seaweed Monster out and with a blast of Godzilla's eye beams, the Seaweed Monster was permanently destroyed.
- The Seaweed Monster has six tentacle like arms in which it can use to ensnare foes and attack enemies.
- The Seaweed Monster can absorb other mutant seaweed to grow even larger.
- The Seaweed Monster can produce other Seaweed Monsters whenever it loses a portion of its body.
The sun will quickly dry it out and eventually cause it to burn.
- The Seaweed Monster resembles The Grinch from Dr. Seuss's stories, as well as Oscar the Grouch from Sesame Street.