The Légal Trap (also known as Légal Pseudo-Sacrifice and Légal Mate) is named after the French player Sire de Légal (1702–1792). It is an attacking trap with which a player sacrifices the queen then followed by a checkmate with minor pieces if Black accepts the sacrifice.
This trap is one of the common traps that any chess player will come across. Both players are just having a normal game opening and none of their moves look bad, until the white captures the pawn and exposes the queen. Black will have to make a choice to take the bait from white and capture the queen, losing the game, though it is really hard for the other player not to take it; that is why this trap works so well. Also if they don’t take the bait, you are still in a great position.