People enjoy skating at the open air Christmas ice rink on the first floor of the Eiffel Tower after its reopening on December 19, 2016 in Paris The ice rink of about 200 square metres and on the first floor of the tower (57 metres above the ground) is open to the public until February 19, 2017. (Photo by Joel Saget/AFP Photo)

Japan' s Kaori Sakamoto competes in the women' s single skating short program of the figure skating event during the Pyeongchang 2018 Winter Olympic Games at the Gangneung Ice Arena in Gangneung on February 21, 2018. (Photo by John Sibley/Reuters)

Japan's Kana Muramoto and Chris Reed compete in the figure skating team event ice dance short dance during the Pyeongchang 2018 Winter Olympic Games at the Gangneung Ice Arena in Gangneung on February 11, 2018. (Photo by John Sibley/Reuters)

Paul Poirier of Canada and Marjorie Lajoie of Canada after training before the Figure Skating Ice Dance – Rhythm Dance at Capital Indoor Stadium in Beijing, China on February 12, 2022. (Photo by Aleksandra Szmigiel/Reuters)

South Korea's Shim Sukhee falls in the women's 1,500m short track speed skating heat event during the Pyeongchang 2018 Winter Olympic Games, at the Gangneung Ice Arena in Gangneung on February 17, 2018. (Photo by Mladen Antonov/AFP Photo)

Italy's Charlene Guignard (L) and Marco Fabbri react to their score after the ice dance rhythm dance competition during the ISU World Figure Skating Championships 2023 in Saitama, on March 24, 2023. (Photo by Kazuhiro Nogi/AFP Photo)

Victoria Sinitsina and Nikita Katsalapov, of the Russian Olympic Committee, compete in the team ice dance program during the figure skating competition at the 2022 Winter Olympics, Monday, Feb. 7, 2022, in Beijing. (Photo by Jeff Roberson/AP Photo)

After some days with temperatures below freezing point, I was out skating at some lakes at the outskirts of Oslo in Norway. After a while I noticed something on the ice. To my astonishment it was a dead frozen frog.