Cryptid is a board game in which the goal is to be the first player to locate the cryptid, a legendary creature, on a map. Each player knows a secret clue as to which cell on the map contains the cryptid. Players take it in turns to ask each other if the cryptid could be on a given cell according to their clue, until one of them guesses the cryptid cell. This game is great fun, but completely loses its interest if one of the players cheats by answering the questions incorrectly. For example, if a player answers negatively on the cryptid cell, the game continues for a long time until all the cells have been tested, and ends without a winner. We provide cryptographic protocols to prevent cheating in Cryptid. The main idea is to use encryption to commit the players’ clues, enabling them to show that they are answering correctly in accordance with their clue using zero-knowledge proofs. We give a security model which captures soundness (a player cannot cheat) and confidentiality (the protocol does not leak more information than the players’ answers about their clues), and prove the security of our protocols in this model. We also analyze the practical efficiency of our protocols, based on an implementation of the main algorithms in Rust. Finally, we extend our protocols to ensure that the game designer has correctly constructed the cryptid games, i.e., that the clues are well formed and converge on at least one cell.