The image looks like a long deflated balloon that is in the shape of an upside down letter U. The edges are not smooth. They are bumpy along the inside and outside of the balloon shape. One end of the balloon tapers to a point.
This Colon icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 5,700 icons, all in the same style and quality.