It was designed as a left-handed homage to Jay Ward's legendary Rocky & His Friends. Unfortunately for creator Mo Willems, Sheep in the Big City didn't have the popularity that Rocky & Bullwinkle have enjoyed since their debut. Introduced as a primetime series on Cartoon Network in November 2000, Sheep is about a singular sheep on the run from a lunatic named General Specific, who is trying to develop a---wait for it---sheep-powered ray gun. Not even Ward was this wacky!
Specific and Sheep were both voiced by ex-MTV personality Kevin Seal, who'd dropped out of sight after leaving the network in the 90's, and hasn't been heard from since Sheep was cancelled in 2002. Seal was also the voice behind the Ranting Swede, who'd appear usually at the end of the show for an angry commentary of some kind that really had 0 to do with the plot of the show.
Anyway, here's the series open: