Lucky is a male dalmatian puppy from the book The Hundred and One Dalmatians and its 1961 animated film adaptation by Walt Disney Animation, and one of the main characters in 101 Dalmatians: The Series. He is one of the most prominently known of Pongo and Perdita's original fifteen puppies, identifiable by the horseshoe-shaped pattern of spots on his back, hence his name.
In the 101 Dalmatians: The Series Christmas episode "A Christmas Cruella", Lucky plays the Tiny Tim role in its A Christmas Carol-esque plot. Early on in the episode, Roger brings Lucky with him to pick up Anita from work, having had to take him to the vet to get out a pine needle that had gotten stuck in his paw. Later, when the Ghost of Christmas Present (played by Lucky's brother Rolly) is showing Cruella De Vil how the Dearlys cannot enjoy Christmas due to Cruella firing Anita earlier in the episode, Lucky is shown limping, his leg having been infected by "piney-pawitis", and the Dearlys cannot afford to give him a leg brace. (Given that this scene occurs within a dream that Cruella is having, it's unclear if Lucky really is suffering this ailment in "reality".)