Crocker tries to program Sparky as an unwitting sleeper agent in his war against Timmy and the fairies.
Denzel Crocker is rewatching home movies of himself trying to figure out where he went wrong in his life. One of those movies shows him on his 11th birthday, the age that according to Da Rulez godchildren loose their fairies forever (because Jorgen states that at 11 years old, kids are old enough to go to therapy). Jorgen comes in and poofs back Cosomo and Wanda to Fairyworld. After they leave, Sparky appears with Boy Crocker and Boy Crocker transmits a fairy tracking microchip that will allow Sparky to bring back Cosmo and Wanda to him when a trigger word is said.
Adult Crocker, upon watching this, realizes that Sparky is Timmy's dog and hatches a plan to go and say the trigger word once he learns about it. However Crocker's Mom videotaped over the tape and the Adult Crocker couldn't hear the whole trigger word (he only got to "under--" before the tape was overrided with Crocker's Mom bellydancing).