For two generic mana, you can tap it to draw a card , but only if you control three or more lands with the same name
About the deck strategy: Search for basic lands, play some slivers, overwhelm your adversaries
You lose out on the Treasure but you gain flashback, and with all the draw-two or draw-three card synergies laying around, this black instant from Modern Horizons 3 can do work
This is so oppressive because of how far ahead it puts the person playing it
Cards like Show and Tell, Sneak Attack, and Channel were all pre-banned because of how easy it is to win the game the turn you cast them (as the Timeless format has shown)
These following cards check both boxes