The zombies are adapting very quickly on The Walking Dead.

At the Comic-Con, the fourth season trailer showed a breed of stronger and savvier undead or 'walkers' as they are called on the hit AMC zombie apocalypse series. They are slowly invading on the territory of the survivors at their prison enclave.

The new show runner, Scott Gimple, said that it will get insane very quickly.

The Walking Dead producers were joined by such cast members as Andrew Lincoln, Danai Gurira and Norman Reedus.

The footage that debuted at the pop-culture convention showed that the survivors' barricaded headquarters have been further strengthened. However, many crowds of walkers are bombarding the gates and this time they are not spreading out anymore.

'Yeah, the walkers are no threat at all this season,' joked executive producer Gale Anne Hurd after Chris Hardwick said that the zombies are just animals.

The clip also revealed a catastrophic event inside the prison that results with multiple deaths. At the end of the trailer, Reedus' Daryl is driving a car and a voice on the radio is whispering, 'Those who arrive survive.'

The Walking Dead creator Robert Kirkman revealed that the villainous Governor played by David Morrissey will come back in the fourth season but the details will come as a surprise to the viewers.

Several Walking Dead fans recommended to the panel what they would like to see in the new season such as Rick and Michonne hooking up.

The fourth season of Walking Dead will debut October 13.