There is no permanent connection between the gut and the rear of the body. Instead, as waste accumulates, part of the gut starts to balloon out until it touches the outer layer, or epidermis. The gut then fuses with the epidermis, forming an anal opening. Once excretion is complete, the process is reversed and the anus vanishes.

It has a vanishing, temporary invisible anus. WTF

In 2024 it was described to possess the ability be biological immortal by undergoing reverse development after the onset of sexual reproduction from mature lobate to early cydippid

And it’s immortal.

Wikipedia