Warning! Potential spoilers for Deadpool #10 (King in Black tie-in) below!
Deadpool just borrowed a smart, but gruesome survival technique that's straight out of The Walking Dead. In order to stave off being infected by the King in Black's symbiote army, the Merc with a Mouth decided to violently chop off his own arm, a move that's proved to be extremely effective in a zombie apocalypse.
In the grand finale of Deadpool's ongoing comic series, Wade Wilson, Elsa Bloodstone, Jeff the Landshark, and an army of monsters battle against Knull's dark army. However, after finding out Jeff, Marvel's cutest hero, is infected by the King in Black's forces, Wade tries to stop his small friend. But, as he puts his arm out to stop him, Jeff takes a bite of his arm, transferring the symbiote goo to Deadpool. In order to stop the infection, Deadpool uses a violent trick to prevent the spread of the darkness throughout his body.
In Deadpool #10 by Kelly Thompson, Gerardo Sandoval, Victor Nava, Chris Sotomayor, and Joe Sabino, Deadpool is pulled from Jeff by Elsa after a bite if taken out of his arm. Elsa smartly reminds Wade that if he's infected, he'll become an indestructible force for Knull's army. Deadpool quickly deals with the problem, saying "you think I won't hack off a limb to keep an evil thing from gaining control of me?" while noting he blew himself up just the week before. Using his sword, Deadpool cuts his infected arm clean off his body.
Deadpool's quick amputation is a move that's often seen in the world of Robert Kirkman's The Walking Dead. On a number of occasions, a character has chopped off a limb after being bitten and infected by a zombie. In the television series based on the comics, Rick Grimes notably amputated Hershel Greene's leg to stop the spread of infection. Meanwhile, in the comics, Rick is forced to amputate Dale's leg after he's bitten. It's a disgusting strategy, but it's one of the few effective ways to stop the bite from spreading.
Thankfully for Deadpool, amputating his arm won't mean he'll be without it going forward. Thanks to his regenerative healing factor, Wade's arm will grow back fairly quickly over time. Regardless, it was smart thinking by Deadpool to chop off his infected arm before the King in Black got full control of his body, which would have given Knull perhaps his most deadly soldier yet. Crisis avoided.