Fish-human hybrids ARE absolutely real in A Song of Ice and Fire. There are several populations of hybrids around the world, including small pockets in Westeors, and at least three prominent characters may be under their psychic influence - Patchface, Damphair, and Euron. Deep Ones cult turns out to be one of the oldest human religions in Westeros, and could once be found all over the continent. Yes, the Nimble Dick dramatic read is here as well.

Disaster Hunters playlist: https://youtube.com/playlist?list=PLEHvft-cyPmBTyeKzxuuBl2EmMW1QPgp8

Secret PreHistory of the Ironborn playlist: https://www.youtube.com/playlist?list=PLEHvft-cyPmA-D6pzGNovu_LuO-QArCB6