This combined animation/Muppet show from Jim Hensen Productions gets an extra half star just because the main characters are all dogs, one of who explains how a time machine has completely altered Dog City in the episode “Future Schlock’ (12 Nov 1994).
Due to the use of a time machine, events were changed in Dog City’s past, which naturally affected Dog City’s future, which was Dog City’s present, of course.

Variants

(1)
  1. Dog City by Jim Henson Productions (12 November 1994).
  2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . written by Jim Henson Productions