Poison counter

A poison counter is a counter that, unlike most other counters, is placed on players rather than objects. When a player has ten or more poison counters, that player loses the game. A player with at least one poison counter is considered poisoned. Interacting with poison counters is seen mostly in black and green.
Cardboard versions of poison counters, similar to tokens, were printed as part of the marketing cards in Scars of Mirrodin block.
==History==
The poison mechanic was introduced on the Legends cards <c>Pit Scorpion</c> and <c>Serpent Generator</c>. The mechanic appeared in sets up until Visions, and was planned as the main theme of Tempest, before it was retired from the game.
 It was next considered for Unglued 2 prior to that set's cancellation.
Poison appeared in a limited capacity in Future Sight, on a pair of futureshifted "preprint" cards with the keyword poisonous. It finally saw print as a major mechanic in Scars of Mirrodin block, which supported the poison counter-granting infect keyword with proliferate. The second set of that block, Mirrodin Besieged, expanded the concept by defining players as "poisoned" if they had one or more poison counters, and including cards that referenced that term.
Poison counters reappeared twice as one-offs in Kaldheim (<c>Fynn, the Fangbearer</c>) and Dominaria United (<c>Ajani, Sleeper Agent</c>), the latter using poison to represent the planeswalker's compleation. These one-offs act like independent Alternate-win or -loss cards, where if something is completed five times the player wins. Phyrexia: All Will Be One followed that up with heavy use of poison counters, including a successor to the poisonous keyword ability, toxic, which grants a set amount of poison to the opponent like its predecessor. Proliferate was also used in the set to synergize with poison, as was a new corrupted ability word similar to the earlier "poisoned" terminology. <c>Etali, Primal Sickness</c> would be the last poison card for this arc, being a call-back to <c>Blightsteel Colossus</c>.
Another one-off poison card appeared in Murders at Karlov Manor, <c>Persuasive Interrogators</c>.
==Removing poison==
Poison is intended to be a fundamentally different win condition from life totals because poison counters cannot be removed, contrasting to life gain. <C>Leeches</c>, from Homelands, is the only exception to this rule. That exception is seen as a severe mistake, by Mark Rosewater, and the card would never be reprinted, even if it were not on the Reserved List. This is something the Mystery Booster test card <c>Puresteel Angel</c> teases. 
Three other cards, , and , can remove poison counters, albeit only for your opponents, making them impractical. Otherwise, the only way for a player to functionally remove their own poison counters is to restart the game with 's ultimate.
Both forms of Melira slow the rate of poison counters, but specifically do not remove any that were already present: <C>Melira, Sylvok Outcast</c> stops the placement, and <c>Melira, the Living Cure</c> restricts it to one poison a turn.
==Rules==
Players with at least ten poison counters, and Two-Headed Giant teams with at least fifteen poison counters, immediately lose the game.
===In the Comprehensive Rules===
104.3d defines the how poison counter works:
122.1f defines the term "poisoned":
704.5 and 704.6 define the various state-based actions, of which two relate to poison:
810.10 and 810.11 specify how poison works in Two-Headed Giant and with "further heads":
==Mechanics==
Poison counters are granted by three keyword abilities.
*Infect
*Poisonous
*Toxic
Many other cards referencing poison counters use wording very similar to the poisonous keyword. Most trigger on any damage, rather than just combat damage. To avoid changing functionality, no errata were made for these cards when the poisonous keyword was introduced. Several Mirage block cards trigger when attacking and not blocked, and Scars of Mirrodin block used a variety of trigger conditions. grants an ability that is functionally equivalent to the poisonous keyword, but did not use it in the card text.
Additional test card mechanics include:
*Poison Modular
==Gallery==
File:Poison counters.jpg|<c>Poison Counter</c> markers as printed in the Scars of Mirrodin block
File:Poison counter ONE.png|Poison counter marker as printed in Phyrexia: All Will Be One
File:ONE Poison counter.png|D10 Phyrexia: All Will Be One spin-down poison counter
==Trivia==
*Poison played a major role in the design of Tempest, but was ultimately rejected for that set.
*The Philadelphia 2023 Unknown Event featured an anti-poison mechanic called Poison Tolerance.
==References==
Category:Counters
Category:Miscellaneous mechanics