(Warning: Spoiler Alert!)

The Walking Dead viewers were left shocked after Rick (Andrew Lincoln) killed Shane (Jon Bernthal) in episode 11, Better Angels. Even more disturbing than his harsh death was that Shane returned as a walker only to get killed again at the hands of Carl (Chandler Riggs).

Reeling over Shane's death and Dale's (Jeffrey DeMunn) the week before, fans have now been focusing on what's to come in this Sunday's season two finale of The Walking Dead. Check out some theories that show viewers have regarding what's to come for The Walking Dead.

Shane And Randal Were Already Infected

Shane could have become infected with the virus when he cut his hand on the bus in episode 11. Since he had already contracted the virus, it would make sense that he changed into a zombie so quickly after Rick stabbed him. Fans also suggest that Shane might have known he had become infected, which is why he provoked Rick to kill him before he could turn.

The same scenario can be envisioned for Randall (Michael Zegen). The prisoner, who was being held in a barn that was previously occupied by walkers, had his wrists cut up from handcuffs. Randall's injuries could have made him susceptible to the virus which would explain his quick turning.   

Virus Mutations

Fans have noticed that Randall and Shane quickly became walkers following their death. Previous episodes have shown that it takes some time before a person can turn into one of the undead. Viewers of the show have been asking, Does the virus take a little longer for some people? One theory circulating the web after Shane's massive meltdown is that the walker virus has mutated and will cause those infected to slowly lose their humanity.

One conversation on the AMC show site believes that the mutation sprang from the season one visit to the Center of Disease and Control (CDC). Corpses found on the highway prior to the CDC visit had not turned into zombies. It's possible that while Dr. Jenner (Noah Emmerich) was experimenting on a cure for the disease it went airborne. Jenner figured this out after taking blood tests from the group of survivors, which would explain why he wanted to kill them all in an explosion. When the doors opened and Rick's group of survivors left, the disease went with them.

We are the Walking Dead

A popular theory circulating fan sites of The Walking Dead draw from the comics of the same name. In an early volume of the comics Rick states, We are the Walking Dead. One theory suggests that in the season finale Rick will finally reveal to the 12 other survivors that Dr. Jenner whispered to him that they are all infected, and therefore are the Walking Dead.

The season finale of The Walking Dead will air Mar. 18 at 9:00 p.m. on AMC. What do you believe will go down between the survivors and the cannibal corpses in the season two finale? Take a look at the season finale preview below.