In the 1991 Marvel Comics Presents story arc Weapon X , the project was designated Experiment X .
Story arc was revealed that it was responsible for bonding the adamantium to Wolverine 's skeleton , making him indestructible .
In the 1991 Marvel Comics Presents story arc Weapon X , the project was designated Experiment X , and it was revealed that it was responsible for bonding the adamantium to Wolverine 's skeleton , making him indestructible .