Trolls are only seen at night, because if they spendmore than a few moments in the sun, they catch sun-sickness and turn to stone.
In Scandinavia there are many boulders with tales tied to them of once having been trolls or being the chosen weapon of trolls hurling them at one another in a dispute.
This illustration was a part of a personal project. A 12 piece series of illustrations based around Scandinavian folklore for a self-published calendar named: Trollkin. See the full series here: [CLICK HERE]