A swindling sleight-of-hand game; victim guesses which of three things a pellet is under WordNet 3.0 & Open English WordNet

The shell game is often portrayed as a gambling game, but in reality, when a wager for money is made, it is almost always a confidence trick used to perpetrate fraud. Wikipedia

Confidence trick. Wikipedia Disambiguation

Confidence trick Wikidata

A game of skill which requires the bettor to guess which of three small cups (or shells) a pea-sized object is concealed under, after the party operating the game rapidly rearranges them, providing opportunity for sleight-of-hand trickery. Wiktionary

A game of skill which requires the bettor to guess under which of three small cups (or thimbles) a pea-sized object has been placed after the party operating the game rapidly rearranges them, providing opportunity for sleight-of-hand trickery; a shell game. Wiktionary