This girl character is based on Tex' Avery's Lonesome Lenny, which in turn is taken from Steinbeck's "Of Mice and Men". It's such a funny concept it's hard to resist it. -Someone who loves his little pets so much, he squeezes them to death. "I'm gonna love you and squeeze you and kiss you..."
I tried to get a little pathos here with shadows of the bars and Stimpy pulling his rubbery gloves along the bars in heartbreaking agony.
I asked Bob to make the girl be light in this run and to have more drawings of her off the ground than on the ground in this run. There are 12 x per step. 7 of them, her feet are off the ground.
There are 5 where she has at least one foot in contact with the ground.
This is drawing 7 and drawing 11. There are 3 more inbetweens very closely spaced between them to make you feel this part of her run, where she is floating in the air. Bob used "tight inbetweens" a lot to great effect.
He also added lots of overlap to smooth out the run. Ren's bouncing overlaps the girl's up and down motion, and then Ren's hair overlaps his.
http://www.cartoonthrills.org/blog/spumco/RenStimpy/1BHB/BobImAlive.mov
That "I'm alive, I'm alive" bit is inspired by "Stranger On The 3rd Floor" - a great movie.