The Battlefield

Laboratory Maniac
Tainted Pact
AI DraftFeb 26, 2026

Laboratory Maniac + Tainted Pact

Overview
Casting Tainted Pact while you control Laboratory Maniac does not by itself cause you to win if your library is empty. Laboratory Maniac only replaces an actual draw event; Tainted Pact exiles cards and may put one into your hand but does not cause a draw. If Tainted Pact tries to exile from an empty library it simply can't exile a card, and no draw/replacement occurs (, , ).
Step 1
Cast Tainted Pact (). It goes on the stack and, assuming no interruption, eventually resolves.
Step 2
When Tainted Pact resolves, follow its instructions: "Exile the top card of your library. You may put that card into your hand unless it has the same name as another card exiled this way. Repeat..." This is an on-resolution loop that exiles top cards and optionally moves one from exile to your hand.
Step 3
If your library is already empty when the resolution tries to "Exile the top card of your library," there is no top card to exile, so that iteration does nothing (no card is exiled and nothing is moved to your hand). The loop cannot make progress by exiling cards and therefore resolves having exiled zero cards.
Step 4
Because Tainted Pact’s effect never says "draw a card," no draw is attempted during this resolution, so Laboratory Maniac’s replacement ability (which replaces a draw that would happen while your library has no cards) does not apply at any point during Tainted Pact’s resolution. You do not win as a result of the spell resolving (, ).
Step 5
If at some later time an effect actually causes you to draw a card while your library has no cards, Laboratory Maniac’s replacement will apply and you will win instead of drawing (subject to other replacement effects or replacement-preventing effects, see Ruling [2021-03-19]).
Resolution
You do not automatically win. Laboratory Maniac’s ability is a replacement for a draw that would occur while your library has no cards in it; Tainted Pact’s instructions exile cards and may move one from exile to your hand but do not instruct you to draw, so Maniac’s replacement ability does not apply during Tainted Pact’s resolution. If a later effect actually causes you to draw while your library has no cards, Laboratory Maniac will replace that draw with a win (see and ). See also Ruling [2021-03-19] for the situation where you can’t win even though Maniac’s replacement applies.
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