, Mill a card: Add . (Activate only as an instant. To mill a card, put the top card of your library into your graveyard.)
The toymaker frowned in bewilderment. None of his creations had ever sneezed before.
(08/12/2022)
If an effect allows you to look at the top card of your library any time or to play with the top card of your library revealed, and you activate Millikin's mana ability while casting a spell, you can't look at the new top card of your library until you are done casting the spell. The same is true if you activate Millikin's ability while activating another ability.
(05/08/2026)
Millikin’s ability is not a mana ability. Players can respond to it, and it can’t be activated in the middle of paying for a cost. A recent update to rule 605.1a has made any abilities that move cards to or from libraries no longer mana abilities.
