Leonard's body explodes when his wand gets broken by Mark Lilly. Leonard's hologram says that Leonard is not dead, but his flesh must all be put together for regeneration. As Mark is still missing a piece when the regeneration takes place, the flesh splits into 500 or so tiny baby-like Leonards instead, each with a big bush of white beard. As each time a tiny Leonard dies, all the others grow bigger and older a little bit. So all the rest must die for the one remaining to become the original normal-sized Leonard.
Hunting Leonards and Lincoln's Re-assassinationEdit
The tiny Leonards are later labeled with numbers written on their foreheads. Some of them die of accidents and by Mark and Randall's purposeful negligence.
One of them, Leonard 67, receives the call that Terry taunts him he's going to kill the zombie Abraham Lincoln again. 67 tells 318 about the assassination plan. Then 187 overhears Mark telling Callie Maggotbone he is going to slaughter them all, and he tells every other Leonard. A riot among the tiny Leonards breaks out with most of them killed by each other. The dozens of remaining little Leonards escape into the city. And each of them has grown bigger and older, more like the original Leonard now than a baby.
Mark then overhears Terry and Twayne Boneraper's re-assassination plan on the former president in the Department of Integration. He hires a hitman who turns out to be Francis Grimes to kill the little Leonards so that the one remaining could save the president. Leonard 254 appears and tells them he's inserted tracking chips on the rest of Leonards and cuts a deal with Mark and Grimes that he gets to be the last one and save Lincoln.
By the time Lincoln has gone to the theater and is about to be assassinated, there are still two little Leonards, 254 and 318, alive. Grimes, who refuses to kill a partner, urges Mark to kill 254 so that the other one could save Lincoln. As Mark is suffocating 254, Leonard 318 successfully intercepts but gets killed in Terry's attempt on Lincoln's life. So 254 finally becomes the remaining and original Leonard.
Leonard 67 is the one who picks up Terry's call informing Lincoln's re-assassination. He first tells 318, then to the rest to save the former president. But he ends up killed by Leonard 122.
Leonard 122 is the first one to kill another tiny Leonard, which is Leonard 67. He does not survive in the end.
Leonard 187 is the one who listens behind the bathroom door to Mark telling Callie that he's going to slaughter all the tiny Leonards. He tells the others which leads to a riot. He does not survive in the end.
Leonard 254 hides himself in the bathroom mirror cabinets when the others are killing each other. He gets addicted to Vicodyn. He cuts a deal with Mark and Grimes to be the last remaining Leonard to save Lincoln, and gives them a tracking device to hunt down the others. Yet Mark tries to kill him when Lincoln's assassination draws nigh. When 318 dies preventing the murder, Leonard 254 becomes the sole surviving normal-sized Leonard.
Leonard 318 is the one first hears about Lincoln's assassination from 67. When all the tiny Leonards start killing each other, he makes himself a cape soaked with blood and says, "There can be only one Leonard." He escapes from Mark by grabbing onto the leg of a bird flying away.
He makes his way inside the theater and dies bravely when he saves the former president from re-assassination by swinging himself between Terry (folded as a paper plane) and Lincoln. He is hit by Terry and bursts into blood.
- Since Leonard may be around 500 years old, the number of tiny Leonards sprouted from his flesh may be related to his age.