A Spanish twin was delivered in a 1-in-80,000 “mermaid” birth — inside an intact amniotic sac — according to a report.

Usually, the amniotic sac ruptures when a mother’s water breaks before labor ensues.

The newborns were successfully delivered via cesarean section on Wednesday in Valencia, The Mirror reported.

The rare outcome is also called a “veiled” or “en caul” birth.

“The first veiled cesarean section I’ve seen and I loved it, and I’m not telling the students anything (although I admit that I’m the one screaming),” OBGYN Ana Teijelo wrote on Twitter.

She also shared photos of the twins on social media, “with permission, of course.”