There is a species of jellyfish which is functionally immortal. When they get too old they simply turn into children again and re-age.

Edit: I’m not saying it’s not biologically immortal, I’m saying functionally immortal because I’m indicating that it can still be killed.

Saying something doesn’t experience aging is not the same as insisting it cannot die.

2+2=4 is not less correct because 2x2 also equals 4.