Shown in the photograph is a real, "happy face Spider!"
Hoax or Fact:
The photograph shared online often purports to show a real, 'Happy Face Spider' resembling a big smiley face. Yes, the photograph is real; the happy faced spider is Theridion grallator.
Theridion grallator is a tiny arachnid found in the rainforests of Hawaiian Islands, and measures just a few millimeters (up to 5 millimeters) in length. The tiny spider belongs to the family Theridiidae and is given the name Happy Face Spider because of the weird markings on the back of its abdomen that look like a big smiley face. The Hawaiian name of the happy face spider is Nananana Makaki`i, which means face-patterned spider. Darlyne Murawski, the photographer from Massachusetts (US) was delighted to capture the unusual creature on camera. The happy face spider is so small that you will need a magnifying glass to see the smiley face.
Notably, each Theridion grallator (happy faced spider) has a unique pattern, which differs from island to island, while some do not have any such markings (see last picture in image gallery). They are harmless to humans and scientists believe they have evolved the patterns to confuse their predators.