He was born when Washesh was having a child, but some Malleo DNA got into the womb and made the child half Malleo, half Waweegee. Walleo was named when Papa Waweegee remembered his old enemy, Wario, so he named his son Walleo.
He went to McDonald's (who has been renamed McWeegee's in the United 'Gees Galaxy) because he was obsessed with their food. He later died. Un Ded went to the restaurant to revive Walleo and Walleo II was created, who joined the Anti-Weegee Alliance. However, he was redeemed by Waweegee and was converted back into his previous incarnation.He has joined the League of Weegees, although he is not supportive of Weegee.