It's a logo of Spiral Bulb reduced to a bulb with a spiral light. This light bulb is like a normal bulb except the bulb part is a spiral instead.
This Spiral Bulb icon is made in flat color style
. This format was developed by Icons8 designer team and became immensely popular for use in web and mobile applications. Feel free to download this icon in PNG format for free, or unlock other formats for $5. Unlike other icon packs that have merely hundreds of icons, this monster icon pack contains 6,100 icons, all in the same style and quality.