They aren't simply a dwarf planet and its moon. they're a binary dwarf planet system. their shared barycentre (the centre of mass around which two celestial bodies orbit) actually lies outside pluto itself. they don't just have one orbiting the other; they dance around a common point in space.
They are literally dancing, so cool, right?
They're both plutinos, trans-Neptunian objects locked in a 2:3 orbital resonance with Neptune. Orcus is also called the anti-pluto because their orbital configurations are roughly opposite. They have remarkably similar orbital periods, yet occupy different regions of the solar system.
They can literally never meet.
Theia was a hypothetical protoplanet, possibly around the size of Mars, that existed approximately 4.5 billion years ago. According to the giant-impact hypothesis, she collided with Proto-Earth, ejecting enormous quantities of material into orbit that eventually coalesced into our Moon.
They literally gave birth to Earth and the Moon; they are siblings, okay @Robinisback
Patroclus and Menoetius is like pluto and charon, but even better
They're nearly equal in size, orbit each other, and share Jupiter's orbit around the Sun. Neither is particularly dominant, and neither is merely an accessory to the other. They're essentially two asteroids holding hands while travelling through space, with Jupiter as their father.
tbh a little embarrassing to get so outclassed on intrasolar bodies but i guess it makes sense because i'm more focused on cosmology and extragalactic stuff