When Gallagher Elementary School began making all boys to wear ties, Moosk enlisted the aid of Nigel Uno, who after some hesitance agreed to join Moosk and his other two tie-hunting allies Froggy McDougal, an insane, imp-like man with a vendetta against ties for eating off his finger in the 1970s, and Windsor, a mysterious boy in army fatigues who refused to share his history with Moosk. The group went to the Tieland Commons Shopping Mall, home of the Queen Tie, to destroy it.
When they entered the Queen's lair and were preparing to blow up all the tie eggs, Windsor took away the detonator and revealed that he was actually the son of Moosk's former boss and was secretly working with the ties to make Moosk an accountant again. Numbuh 1 and Moosk fled and were conveniently greeted outside by Hoagie and Wallabee in a S.C.A.M.P.E.R. However, Moosk decides not to run away and instead makes a suicide attack against the Queen Tie, jumping into its mouth and clamping it shut just as it began to attack the S.C.A.M.P.E.R. and destroying it. Moosk tells Nigel that as long as he stopped the queen ensured that kids would never be forced to wear ties again, he will have done good.
Afterward, Moosk became an accountant again. While working, Windsor gave Moosk a package that had arrived as the office addressed to him and told him to keep working. When Moosk opens the package, he finds a can of spray starch, reawakening his tie-hating personality, and begins destroying the office. Outside, the mailman takes off his disguise, revealing himself to be none other than Nigel.
Moosk was one of the characters that did not appear in Operation: Z.E.R.O..