UNCANNY X-MEN (1963) #391

Beast has discovered a cure for the Legacy Virus. The catch: the first mutant to use it dies! After many ours of laboratory work Beast emerges with a cure for the Legacy Virus. He made the cure from the codes he deciphered from Moira’s notes on the virus. Xavier, Cecelia Reyes, Gambit and Wolverine congratulate Beast, who explains to them how the cure works. However, Beast and Cecelia realize that the cure can only be released after its host uses his or her power, which will then kill him or her.…