Humans are designed to see patterns; especially to find faces.
Faces need not be detailed; two triangles and a jagged line carved into a pumpkin, two dots and an arc, both are instantly recognized.
Humans are also hard wired to like symmetry, especially bilateral symmetry, which serves as a marker for good genetic strength. So it is no surprise that we spot any number of fantastic creatures in the bedrock exposed by the falling tide on the shores of the Penobscot River.
On the right day, and at the right tide, it makes for a very distracting paddle.