Sharks are the Klingons of the animal kingdom.
"As macabre as it seems, it's not exactly a secret that in some species of shark the unborn dine on their siblings while still developing in the womb.
But it turns out we don't know the half of it. A new kind of ultrasound device has provided biologists with a detailed view of this common act of cannibalism, revealing they don't just nibble on their neighbour. Embryos will travel between wombs to feast."
https://www.sciencealert.com/new-underwater-ultrasound-tool-discovers-the-lengths-baby-sharks-go-to-for-a-meal
"As macabre as it seems, it's not exactly a secret that in some species of shark the unborn dine on their siblings while still developing in the womb.
But it turns out we don't know the half of it. A new kind of ultrasound device has provided biologists with a detailed view of this common act of cannibalism, revealing they don't just nibble on their neighbour. Embryos will travel between wombs to feast."
https://www.sciencealert.com/new-underwater-ultrasound-tool-discovers-the-lengths-baby-sharks-go-to-for-a-meal