Lake ball

The rolling motion of the waves gathers debris in the water and eventually will form the materials into a ball.

[1][2][3] The earliest known reference to lake balls is Walden: There also I have found, in considerable quantities, curious balls, composed apparently of fine grass or roots, of pipewort perhaps, from half an inch to four inches in diameter, and perfectly spherical.

These wash back and forth in shallow water on a sandy bottom, and are sometimes cast on the shore.

At first you would say that they were formed by the action of the waves, like a pebble; yet the smallest are made of equally coarse materials, half an inch long, and they are produced only at one season of the year.

A specific type of lake ball, a larch ball is a structure created when Western Larch needles floating in a lake become entangled in a spherical shape due to the action of waves.