From the rabbit hole…

Both structures are created by cyanobacteria.

The name “cyanobacteria” (from Ancient Greek κύανος (kúanos) ‘blue’) refers to their bluish green (cyan) color,[5][6] which forms the basis of cyanobacteria’s informal common name, blue-green algae.[7][8][9][note 2]

Common blue-green algae has magic properties!