Chunk

Chunk is a rock-like toy from Sunnyside Daycare that appears in Toy Story 3. Chunk has protective shoulder spikes, poseable oversized limbs, and fists ready to smash anyone who gets in his way. He also has a hidden head spike which when pressed down on switches Chunk's facial expression from friendly to fierce. He was one of Lotso's henchmen. He is voiced by Jack Angel.

In the end credits, when Sunnyside is turned from a prison into a paradise by the new leaders Barbie and Ken, he is shown to be not very bright, but durable enough to handle the abusive toddlers in the Caterpillar Room, and he takes turns with Twitch to experience the rough playtime. During the "beach party" at the sandbox, Chunk is shown playing beach volleyball with Jack-in-the-Box as they bounce a Luxo ball back and forth between each other.

Toy Description
From Official Website:

"Chunk will rock your world! This gargantuan creature sports protective shoulder spikes, while his ferocious fists are ready to smash whatever enemy gets in his way. Chunk's oversized limbs are fully posable, making him ready for hours of imaginative fun. As an added bonus, the press of a hidden head spike will spin Chunk's expression from friendly to fierce! No batteries necessary."

Trivia

 * Chunk appears to be based on the short-lived Rock Lords toyline from the 1980s.
 * Many of the Chunk toys created have the face feature, however some have it changed by pressing the spike on the top (as seen in the picture below toy description), and the others have it changed by swiveling his face.