The spire-like shape of Thielsen attracts lightning strikes and creates fulgurite, an unusual mineral. Their intended destinations included Thielsen, which was climbed and sampled for its fulgurite variant. By examining the outcrops in which the fulgurite samples were found, Sponholz et al. The approximate age of the fulgurite was determined using thermoluminescence (TL). Glass that forms when lightning hits sand, as in the film, is called fulgurite. He ended up being accidentally struck with lightning by Electro, temporarily turning him into fulgurite. The fulgurite samples dated back approximately 15,000 years to the mid to upper Holocene.