Which 1986 Pixar short is named after a lamp?

The 1986 Pixar short named after a lamp is Luxo Jr.

Written and directed by John Lasseter, Luxo Jr. is a roughly two-minute computer-animated short about two desk lamps: the larger Luxo Sr. and the energetic younger Luxo Jr. The smaller lamp plays with a ball, accidentally deflates it and then finds another toy, giving the film a surprisingly expressive family story without dialogue.

Lasseter developed the film from experiments modeling a Luxo desk lamp. Its simple subject also showcased computer-animation techniques, including shadow mapping and self-shadowing. The short debuted at the SIGGRAPH computer-graphics conference in Dallas in 1986 and received an enthusiastic response.

Luxo Jr. became especially important to Pixar’s identity. The hopping lamp eventually became the studio’s mascot and appears in Pixar’s famous production logo. It is sometimes confused with Knick Knack, Red’s Dream or Tin Toy, but those are separate Pixar shorts; only Luxo Jr. is the title built directly around the lamp character.