Agent R appears in the O.W.C.A. Christmas party and at the end of "Phineas and Ferb Christmas Vacation!". Unlike the other agents, it has three hats, probably because it can't put one in between its antlers so it puts three on its antlers. At the end of the Christmas episode, it is seen on Santa's sleigh so it is likely one of Santa Claus's reindeer (Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner or Blitzen).
- Its secret agent file says it has powerful antlers that are useful but cumbersome for wearing its hat. It is rumored to be able to fly. It also enjoys cookies, eggnog and salty snacks.
- In Phineas and Ferb Save Summer, it now wears only one fedora between its antlers.
- "Phineas and Ferb Christmas Vacation!" (First appearance)
- "Phineas and Ferb Save Summer"
- "O.W.C.A. Files"
- Where's My Perry? (Agent file)