Bannister's Thugs are the secondary antagonists of the Phineas and Ferb episode, Sidetracked. They are three unnamed burglars who are under the employ of Professor Bannister.
Role
The thugs were first seen during the beginning of the episode, where they broke into a warehouse in downtown Seattle to steal some technology. As the thugs drive off in their truck carrying the stolen equipment, Perry the Platypus pursues them on their tail with a motorcycle. Though Perry was able to use a grappling hook to catch the truck, he is stopped by incoming C.O.W.C.A. Agent Lyla Lolliberry (Professor Bannister's nemesis), who tells him that he has no jurisdiction in Canada as they already passed the border. Lyla climbs onto the truck, but her weight causes the donut arm to break, causing the three thugs to drive away scot-free. Perry is forced to return back to the U.S. and he develops a bitter hatred towards Lyla for letting the thugs escape.
However, two months later, Perry and Lyla were assigned on a new mission to protect the local Canadian symbol of national unity (Albert the Moose), as Bannister arranged for Heinz Doofenshmirtz to kidnap and deliver the moose to him as part of their U.S.-Canadian evil scheme exchange program. As Lyla and Perry confront Bannister in his helicopter, Bannister confessed of his true plan to destroy Canada's national pride and annex Canada into his real homeland Greenland, so that he can put in a new national anthem for Greenland and reinvigorate its low national pride. Bannister also revealed to having created two magnetic androids, and that the thugs (who are inside the helicopter playing cards) were assigned to steal the parts he needed to make the androids. It was then Perry realized that Lyla only let the thugs escape because they would lead them to Bannister.
As Bannister sets his androids to attack Lyla and Perry, Doofenshmirtz (upon realizing how complicated Bannister's plot really is) decides to go play cards with the thugs. However, the thugs engage into a brawl with each other and Doofenshmirtz after the latter wins a game against them, just as Lyla and Perry manage to defeat the androids before having Bannister captured. The thugs are then finally arrested along with Bannister for their crimes, as they are last seen being escorted into a police van.