When the power cord stretches enough to pull the plug out, the coyote climbs out and finds himself vibrating sporadically. To "punish" the book, Wile E. walks over to it and prepares to tear it in half, but one of the vibrations does the job for him.
When the power cord becomes too long to hold, the coyote climbs out and begins trembling. To "punish" the book, Wile E. intends to rip it in half but ends up being distracted by one of the tremors.