This photo of a crow has gone viral because all it not as it seems

Just in time for Halloween - the spookiest time of the year - an optical illusion has got the Internet squawking, or purring, with excitement.

A viral image, tweeted by @RobertMaguire_ and originally found on Reddit, has gone viral for an unexpected reason.

The photograph, which at first glance appears to show a black crow looking sideways, is actually not a crow at all. In fact, the picture is actually of a black cat. Move over "the dress", there's a new sheriff in town.

Needless to say, some of the online responses are hilarious.