Far from inanimate objects, corals are made of creatures in the same phylum as jellyfish. What appears to be a singular structure is actually formed of hundreds or thousands of individual animals named polyps, and those polyps, like any animal, require sustenance. Reef-building polyps generally benefit from symbiotic relationships with algae that photosynthesize energy from light, but by night these polyps feed directly on microscopic organisms, and in rare cases, coral colonies can even "fight" with one another for territory, spilling their guts onto a neighbor to digest their combatant. This surprisingly dynamic behavior often goes unseen, but as a time-lapse video featuring corals and related species like anemones shows, it can be truly beautiful.