Kettle, or pothole, lakes are seen everywhere in the formerly glaciated tracts of the Nordic countries where moraine deposits prevail. They are often very small, can be extraordinarily deep given their size, and have small catchments or are entirely feed by ground water. They are often surrounded by conifer forests, mainly Scots Pine (which isn't Scottish at all, but that is a story for another day). Most are in a process of being overgrown by expanding blanket bogs in the ecological succession Germans so accurately designate 'Verlandung'. Because of their boggy surrounding, often dark peat-stained waters, and the depth, Nordic Folklore populate these lakes with scary creatures such as the Water Sprite ('Nøkken' in Norwegian), and stories about people - mainly women, apparently - who have been lured into the dark waters are plentiful.
In my neighbourhood there several of them and this one is a prime example. Viltrox 23mm f/1.4, Nikon Z fc. One should not venture out to the water edge despite the surround bog now is freezing over. The substrate is like a quagmire and highly dangerous. So I kept my distance in order to tell the tale.