Riff Raff and Magenta

Whenever Riff Raff and Magenta enters the
battlefield, each player exiles the top card of their
library. You may cast one of the exiled cards
without paying its mana cost. Whenever you cast a
spell from exile, each opponent loses 1 life and you
gain 1 life.
—
"Madness takes its toll, but listen closely..."
"Not for very much longer..."