Gusano is a Vermis. He was Susan's third creature.
His card, along with the Move Cards Volcano Burst and Magma Blaster, was found outside the White House by Margaret. Not knowing it was a Card Capsule, she brought it to President Hathaway, who instructed her to make an omelet. When she opened the Capsule, the cards fell into the fire and activated. After the two people fled, Team Monster arrived almost immediately. He battled and beat senseless both Panther and Arthro. Lati very nearly lost as well, only winning by making him swallow a Tragedy of the Sphere. He was later revealed to be a 26 on the Power Scale, explaining his power. The next episode, he battled and defeated a Smilodon. The next eipsode, he battled and defeated a Thylacosmilus. The next episode, he battled and defeated a Future Bird.
The first copy of the Volcano Burst Move Card was in his Card Capsule, and was activated along with him. He never used it until after his capture, however.
The first copy of the Magma Blaster Move Card was in his Card Capsule, and was activated along with him.
He is the strongest creature to appear in the series. It has been confirmed that he hurt Panther and Lati so bad that they have broken bones.
He always defeats his opponents without much trouble at all.