Slinky Dog

Slinky Dog, or Slinky for short, is a toy dog who appears in Toy Story and Toy Story 2. Slinky, often referred to as "Slink," possesses wooden front and hind quarters, with a Slinky as his middle. The character's name and basic appearance are modeled on a much older pull-toy dog, manufactured by James Industries (the Slinky company). When Toy Story was released theatrically in late 1995, the original toy had been out of production for at least five years. Thus, while toys of Woody, Buzz, and even a special edition Mr. Potato Head had been rushed to the market, company CEO Betty James had "mold problems" reworking the toy, and it was some time later when Slinky Dog toys (now bearing the likeness of the Toy Story version) were shipped to stores.

Toy Story
In the first film, Slinky is loyal to Woody, and continues to defend him... until he sees Woody waving Buzz Lightyear's severed arm. After the toys learn from Bo Peep that "Woody was telling the truth," Slinky, also feeling guilt, uses his elastic middle to help pull Woody and Buzz into the moving truck (ultimately rebounding back when he wears himself out).

Toy Story 2
In Toy Story 2, after Al McWhiggin of Al's Toy Barn steals Woody, Slinky goes on the mission led by Buzz Lightyear to rescue their valuable friend. Slinky's coil is used as a bungee cord to jump from Andy's house. When the toys break into Al's apartment, Slinky uses his coil to tie Jessie and Bullseye. Later, Slinky controls the pedals of a Pizza Planet delivery truck that the toys hijack to chase Al to the airport.