There is an odd species of creature with striking resemblance to a reindeer called Rudolphie, it has a red hue on its nose due to constant exposure to the cold condition of Arctic tundra and being bred by the Yeti to pull heavy sleigh. Eyewitnesses reported they saw the nose of Rudolphie emitting alternating red and blue flashes of light in close proximity, any idea what evolutionary pressure or diet could led to this bizarre encounter?
It's a well known phenomenon called chromatophorism. Rudolph's nose is externally the normal color, but when sensing danger or otherwise aroused, the nose is flared to increase airflow and sensitivity; engorged with blood, the nose swells in time with the heartbeat, and the internal layers get exposed.
They do not actually emit light, but they do contain a phosphorescent pigment that makes it appear similar to a police blinker.
It is an aposematic display meant to convey that the reindeer is now alert and may be in fight-or-flight mode, so you better step carefully around it or risk being gouged.
Some reports claim that the same signal is also used by male reindeers during mating chases, to induce fleeing females to slow down and pull over.