Female hooded seals have some unusual mate preferences: they're allured by males that have the most attractive nasal balloons.
What are nasal balloons, you ask? Male hooded seals have evolved specialized pinkish-red nasal cavities that they can blow up like bubblegum. To get a female's attention, the male will often blow up his balloon and start bouncing it around. It's a bizarre sight, to say the least. The cavities can expand to roughly the shape of the seal's head.