Stilt-legged flies (in the family Micropezidae) make their living by pretending to be other insects — in this case, an ant. The forelegs of this stilt-legged fly (Taeniaptera trivittata) are bright white to attract attention, and the fly holds them out straight in front of it like the antennae of an ant. Other Micropezidae pretend to be ichneumon wasps.
Outside of pretending to be much scarier than they really are, stilt-legged flies aren’t harmful to humans and generally eat decaying organic matter (although some are predators as adults). We don’t know too much about these fascinating little insects, which is kind of a shame — you’d think there would be whole teams studying a family of “dancing” flies!