When the Dr. Animo arrives in Mutant Cockatiel to the Museum of Natural History in Washington DC, he shows the power of his Transmutor to the Tennysons by reviving a mammoth to distract Ben who had transformed into Four Arms. Dr.Animo then revives the Tyrannosaurus and uses it as transportation.
It goes in search of Tyrannosaurus Professor Kelly to get the prize so the truth, even so is found by Ben. Ben stops to protect Kelly, and as Stinkfly, defeats Dr. Animo and the transmutor falls to the floor. With the transmutor destroyed, the Tyrannosaurus becomes a pile of bones again.
Dr. Animo used it to reanimate and revive a Tyrannosaurus from a skeleton. Animo then used the revived T. Rex as transportation, and to attack and try to kill Kelly. When Ben, as Stinkfly, destroyed Animo's Transmodulator, the Mutant Tyrannosaurus became a lifeless skeleton again, which then collapsed.