Tardigrades are just awesome organisms. They have eight legs and live in water-based environments, but they're also microscopic, so you would need a microscope to see them up close.
On the other hand, they are actually quite complex creatures and despite their size, they can exhibit legitimate complex mating practices, as referenced in the Zoological Journal just last month.
Here, we see two different behaviors of the bisexual tardigrade: both egg deposition and seminal ejaculation.
This is the first time this kind of behavior has ever been captured of tardigrades on camera, so it's a pretty big finding. More importantly, the behavior helps the scientists to distinguish between the males and the females, since the two look the same, generally speaking.
You can bet more research involving the social behaviors of tardigrades is inevitable.