Chancellor of the Mulligan (UNK-RA07B) - Unknown Event

You may reveal this card from your opening hand. If you do, at the beginning of the first upkeep, shuffle it into your library and draw a card.
Menace
When Chancellor of the Mulligan enters the battlefield, draw three cards. When you do, any number of players mulligan. (They shuffle their hand into their library, then draw that many cards and put one of them on the bottom of their library.)