He fuses to her.

A male anglerfish can fuse to his mate.

In some deep-sea anglerfish, the tiny male bites a much larger female and stays there permanently. Their tissues can fuse and their circulatory systems connect, turning the male into a nutrient-fed sperm supplier.1

A 2026 mathematical model found that this strategy is favored when mates are hard to find and the costs of staying attached are low. That result explains a possible evolutionary pressure; it is a model of the trade-off, not a direct measurement of every anglerfish species.2

#WeirdScience #MarineBiology #AnimalBehavior #Evolution