Walkers

"I kill zombies that are better men than you before breakfast!"

- Rick Grimes

Multiple walkers appear as cameos in Rick Grimes vs Walter White. They are seen being shot by Rick. They are played by Neil Blan, Amy Bury, Ray Timmons, and Tom Walsh.

Information on the Cameo
Zombies, usually referred to in The Walking Dead universe as "walkers", are the eponymous main antagonists of The Walking Dead.

Zombies are undead creatures. They are bodies of deceased humans that have in some way been reanimated and move about, but they don't show any brain or vital functions. Therefore, they are not considered to be alive. In most cases, they are depicted as mindless corpses with a desire to eat human flesh.

In  The Walking Dead, everyone carries a pathogen that can bring the dead back to life. After a person dies under any circumstances, the pathogen will reactivate parts of the brain that support necessary vital systems, and it will reanimate the corpse. Because only critical parts of the brain are activated, Walkers are known to have no memory of their previous selves (only a physical resemblance remains) and do nothing but attack and eat the living. Although Walkers don't form a real threat as individuals, they are especially dangerous when traveling in a large group or "herd". The only way to truly kill a Walker is by damaging its brain. Because they are technically dead and rotting, Walkers typically have decaying flesh and raggedy clothes covered with blood.

Appearance in the Rap Battle
A short clip of a walker was shown in the April 15th Monday Show. They appeared in the battle and were killed by Rick Grimes.

Trivia

 * They are the fourth cameos to get killed, after Urban Ninjas, Mustached Cowboys, and Blackbeard's Pirates.
 * They attended to Heroin Joke's funeral where they sang the song Amazing Grace.