Fluffy clouds that radiated pastel swirls caught netizens' attention, with photos of the "rare" sky display going viral.

"The unicorn is here," Anne Elle Salikala said in jest on Facebook as she posted a video and photos of the colorful cloud, taken in Pagadian City, Zamboanga del Sur.

Netizens have been swooning over the photos as Salikala's post has generated at least 18,000 reactions and at least 85,699 shares on Facebook.

ABS-CBN resident meteorologist Leonilo Millares identified the multi-colored phenomenon as "cloud iridescence" or the display of rainbow colors caused by the distribution of light through "small water droplets present in cumulus or circus clouds."

"This phenomenon will not occur if the water droplets that formed in the clouds are too big," Millares said.

Cloud iridescence are considered rare because people in the Philippines are not keen on reporting or documenting every sighting of the phenomenon, he said.

Millares said cloud iridescence can happen anywhere, even on nights when the moon shines bright, provided that cloud formations carry the minuscule droplets needed to refract the light.