Comments of chapter undefined of JJK : With a Shotgun in Jujutsu Kaisen

so this might be too OP how you implement it but i think a final weapon that would be cool to have as a summon would be the Black Barrel from the nasuverse. it’s ability is to measure the life(?) of an object and shoot out the same amount of energy to kill it so like our earth has a lifespan of billions of years so the barrel would shoot out the same energy to destroy the earth. now in the fgo game it takes time to acquire a target then to get a read on the lifespan and even to shoot it needs a demi-servant with a command spell so it’s pretty much a final shot and you get it only once.