Ash asked Law to perform the Immortality Operation

Realistically, it might've been when he saw Ho-oh in the first episode. He saw it and said that he wanted to go on his journey forever, therefore granting him immortality AND giving the Pokemon company no right to write him off.

ash got that good anti-aging cream

ong i need to get me some of that

Ash aint ever turning into Ashes🗿

i like that, that was cleaver