One summer, when your great grandfather was plowing the small field near the forest, the iron plow hit something very hard beneath the ground and split in two. Your great grandfather cursed, he bent down and saw a small formless stone, when he grabbed the stone it started to move, two small eyes opened, the stone had arms and legs and mouth, the stone was quick. it broke the hands of your great grandfather, then it borrowed itself deeper beneath the black soil and disappeared.
He called the troll Rusketus (sunburn), for it was not the iron plow that had awakened it from it's slumber, but the rays of the spring sun. Your great grandfather never plowed that field again, it's part of the forest now.
Family tale noted in a Finnish diary from 1820.