HechoAmano: All the black stuff under the water at the beach there, are those sea urchins?

Deleted User: Those are Turds.

HechoAmano: We were in Akumal years ago, and the beach we were at was nice, but looked exactly like this, and when we got there staff informed us the black spots were groups of sea urchins. So, lay on the beach, don't go in the water unless you had shoes on.