Day of the Triffids? Night of the Trifid

The Trifid Nebula, Messier 20, is a star-forming region, rich in gas and dust.

The central nebula appears divided into three(ish!) lobes by filaments of foreground dust. The red colour is due to hydrogen-alpha emission, arising from gas ionized by radiation from newly-formed hot stars. At the margins of the nebula, dust reflects the blue light from the same stars.