Amoonguss is Ui's third Pokemon she caught in Full Moon's Full Pokemon Journey's second season in the episode "There's a Foongus Amoonguss!". It was confirmed male when he had a crush on Ui's Leafeon who was female.
As a Foongus, he is very shy to strangers, and often runs to Ui's arms in fear due to its timidness.
In What's In a Nickname?, he was officially nicknamed Angus by Ui, and even nicknamed the other Pokemon she has owned.
In "The Ghost Of The Marionette!", after being taunted by Team Rocket, Angus suddenly learned Solar Beam and blasts Team Rocket into the sky.
In "Azusa's First Love!", Ui was conforting Angus who watched Bella, Cassie and Lily who battled Team Rocket but they lost, Just as Inkay was about to attack Ui with Psybeam, Angus shielded Ui at the last second and took the hit much to Ui's horror and nearly making Ui cry, however, hearing Ui's heartfelt call and crying caused Angus to evolve into Amoonguss and learning Seed Bomb and Spore in the process.
Angus's known moves are: Spore, Giga Drain, Seed Bomb and Solar Beam, and his ability is Effect Spore.