Smallville Season 8 Episode 21

Injoke: Clark mentions he's at the corner of Marshall and Beeman, a reference to James Marshall and Greg Beeman, producers on the show.

Neutron
Neutron first appeared in Action Comics #525 and was created by Marv Wolfman and Joe Staton. Petty thug Nathaniel Tryon was caught in a nuclear meltdown and transformed into sentient nuclear energy. Tryon was able to give himself a body of sorts using a containment suit, and has super-strength and the ability to project nuclear blasts.

Livewire
Livewire first appeared in Superman: The Animated Series and was voiced by Lori Petty. A Metropolis radio shock jock, Leslie Willis, the woman was struck by lightning during a rock concert and was transformed into a being of pure electricity. She was later introduced into the comic book continuity in Action Comics #835 by Gail Simone and John Byrne.

Parasite
In the comics, the Parasite first appeared in Action Comics #340 and was created by Jim Shooter. Raymond Maxwell Jensen was exposed to contaminated biohazard material and gained the ability to drain energies from individuals. He battled Superman on numerous occasions. Post-Crisis, Darkseid engineered another man, Rudy Jones, to gain similar powers. Typically, the Parasite has been a bald purple-skinned humanoid who can gain the superpowers, intellect, and memories of anyone he touches. The powers typically revert back to the person they're stolen from after an indeterminate period of time.