Deadpool #4 2009

In Deadpool #4, Wade Wilson learns his healing factor is failing due to gamma radiation exposure. Dr. Killebrew reveals the only potential cure requires a blood sample from the Incredible Hulk. This leads Deadpool, accompanied by Siryn, to confront the Hulk on his island. A memorable battle ensues, with Deadpool ultimately outsmarting the Green Goliath to secure the vital blood sample. This issue is notable for featuring a classic, action-packed showdown between two iconic Marvel characters and is a key chapter in Deadpool's ongoing struggle with his unique physiology.