The images feature sand castles created by an artist, not natural

Facebook posts shared hundreds of times show photos of a structure on a beach, which they claim are fulgurites created "when lightning strikes sand". The posts are misleading; the pictures show elaborate sand castles made by an artist. 

How to build the perfect sandcastle, Family

Beach

Art Mediums, Definition, Types & Examples - Lesson

Fact check: Images show artist-created sculptures, not fulgurites

Tracing the Ephemeral: What is Left Behind, by Huma Kabakci

For Sue McGrew, sand castles are serious works of art - The Washington Post

Beautiful Animal Art from seashells found at the beach on Trendy Art Ideas

Otherworldly Sandcastles By Matt Kaliner - IGNANT

Ephemeral Art: A Guide to The Beauty of Transience

These Brutalist Sand Castles Might Be Cooler Than the Real Thing - WebUrbanist

Fact check: Images show sand sculptures by an artist, not lightning strike fulgurites

Sand castle made by nature hi-res stock photography and images - Alamy

Calvin Seibert Sculpts Impressive Modernist Sandcastles

How to Make a Hardened Sand Castle Out of Baking Soda