The Strange Attractor is an item introduced in The Binding of Isaac Rebirth. It is a dark, monochrome magnet.
On pickup, Isaac's tears will turn silver and a reversed, grey magnet will be placed on Isaac's head.
Isaac's tears will draw enemies and pickups (Hearts, Coins, etc.) into him. This is very counter intuitive, since this means enemies will start moving towards Isaac at greater speeds, making enemies like Lust incredibly hard to avoid.