Earlier this month, a beagle that survived a puppy gas chamber at an overcrowded shelter in Florence, Ala., was dubbed the "miracle dog." Now he's up for adoption again, and this time, hundreds of potential owners want to take him home. Here, a brief guide:

Who is this miracle dog?
A 5-year-old beagle who was left in a box outside of an Alabama shelter. He was scheduled to be euthanized on October 3 along with 18 other dogs. An animal control officer put several of the dogs into the gas chamber and set it for the standard 17-minute cycle. When the officer returned to fetch the bodies, the little beagle was still alive and wagging his tail.

How did he survive?
No one really knows. The dog might have had a slight cold and been breathing shallowly. Variables like the number of animals in a chamber, the concentration of the carbon monoxide, and a dog's age and health can also affect survival chances. 

Is this really how dogs are killed?
Yes. The gas chambers are stainless steel boxes typically the size of a truck bed. Seven or eight dogs are put in at a time, and the chamber is sealed. Than an operator pushes a button and carbon monoxide is slowly fed into the chamber. Typically, the dogs go "to sleep slowly," says Phil Stevenson, the spokesperson for the city of Florence, Ala. Eighteen states, have banned gas chambers in some form. The ASPCA advocates lethal injection of sodium pentobarbital over the gas chamber as a faster, safer means of euthanizing animals. 

Where is the miracle dog now?
After his miraculous survival, he was put in a short-term foster home in Tennessee. There, an animal rescue worker named the beagle Daniel after the biblical character who survived a lion's den. Daniel later left Tennessee, and is now up for adoption at the Eleventh Hour Rescue in New Jersey. "He's very fun loving, he's very sweet," says foster mom Jill Pavlik. After Daniel's story was published in a New Jersey paper, Eleventh Hour received more than 200 emails from people interested in adopting him. The organization hopes some of these people will adopt other pups instead. "We have dogs that are just as wonderful as him that were on death row, but didn't walk out of a gas chamber," says Eleventh Hour President Linda Schiller. "They're happy and they're wagging their tails and ready to be adopted."

Have other dogs survived gas chambers?
In 12 years, recalls Stevenson, Daniel is only the third dog to survive. "It's just very, very rare," says the shelter's director, Vinny Grosso. When an animal does survive, the shelter policy is to find them a home. Earlier this year, a terrier puppy in Oklahoma survived not one but two euthanization attempts when one injection to his arm and a second directly to his heart failed to kill him.

Sources: ABC News, Los Angeles Times, NY Daily News, TIME