In certain species of Anglerfish, the males are too weak after birth and so they immediately look for a female.
“Once the male finds a female, he quickly latches onto her with his teeth to start a process that sounds like the stuff of science fiction. The male begins to fuse his body to the female, and his body enlarges like a deformed tumour. As it grows, it begins to lose limbs and organs. Its fins fall off, its eyes cease to function, and it ceases to have its own circulatory system. The blood that carries oxygen through its body comes from the female.”
These creatures are all created by God, but may be changed due to mutations.
Picture from: https://pixabay.com/photos/anglerfish-fish-museum-ocean-life-6554995/ accessed on 12/13/22.