Install Parasite only on a rezzed piece of ice.

Host ice has -1 strength for each virus counter on Parasite and is trashed if its strength is 0 or less.

When your turn begins, place one virus counter on Parasite.

Parasite is an Anarch virus that can be used to trash ice. It is often paired with Datasucker to accelerate its trashing capabilities or even to trash ice at paid ability speed in the middle of a run using cards like Clone Chip and Personal Workshop. Parasite has three abilities.

Constant Ability
Parasite must be installed hosted on a piece of rezzed ice

Constant Ability
The piece of ice hosting Parasite has its strength lowered by 1 for each Virus Counter hosted on Parasite. The host ice is trashed if its strength is ever 0 or lower.

Triggered Ability - Conditional
Trigger Effect
Runner's turn begins Place 1 virus Counter on Parasite


Page 5, Column 1, Paragraph(s) 7-8, FAQ
Parasite cannot be hosted on Djinn. A card or counter can only be hosted in one place at a time, and Parasite has the restriction that it must be installed on a piece of ice.

If a piece of ice hosting Parasite is derezzed, the Parasite continues to collect virus tokens, but the hosting ice has no strength while derezzed and therefore cannot be trashed by Parasite unless it is rezzed again.

Related FAQsEdit

  • FAQ 1.0.18 - regarding Parasite, Ice Carver, Chum, and Enigma: constant strength modifiers are totaled up in order to determine a piece of ice's strength at any given time.

Related RulingsEdit


  1. Parasite, Ice Carver, Datasucker v. Tollbooth Ruling
    Corp has Tollbooth. There is a Parasite on it with 4 counters, making it currently strength 1

    Runner has Ice Carver in play and runs. "All ice is encountered with its strength lowered by 1."

    Is the ice trashed before the runner has to lose 3 credits? I was reading somewhere about the active player choosing the order of effects, and if it is the runners turn, could he choose to process Ice Carver effect first, then Parasite, killing it before he has to pay the 3Credit

    In a follow up question, lets say that there was only 2 Parasite counters on the ice, but the runner has Datasucker in play with 2 tokens on it. "Hosted virus counter: Rezzed piece of ice currently being encountered has -1 strength until the end of the encounter. " That says "currently being encountered", so I think you would have to lose 3Credit from Tollbooth before you get to use it, whereas Ice Carver says that the ice is encountered at strength -1.
    The Tollbooth would be trashed before its conditional ability triggered. You have two different constant effects (Ice Carver and Parasite) which combine to knock it off before the Tollbooth can force the Runner to pay credits.

    Datasucker counters could not be used until after Tollbooth's ability. "When encountered" conditional abilities are resolved before there is an opportunity to trigger paid abilities.
  2. Breaking Subroutines on NEXT Silver, Ashigaru Rulings, Question 1
    Suppose there are two copies of NEXT Silver rezzed, and no other NEXT ice. The runner has Clone Chip, Grimoire, and Grappling Hook installed. The runner encounters one of them, uses Grappling Hook to break one subroutine, and then uses Clone Chip to bring out a Parasite on the other NEXT Silver, killing it immediately.

    Is the one subroutine of the ice being encountered broken, or unbroken?

    If it is broken, and if Chum applies, would Chum deal damage?

    The subroutine on NEXT Silver is broken, and Chum would not deal the Runner any damage.
  3. Trash Effect Ownership Ruling
    I am curious about which of these scenarios would be considered the Runner trashing a card:

    Scenario 1:
    The Runner has installed a Parasite onto a piece of ice, and the ice is eventually reduced to 0 strength, resulting in Parasite's effect trashing it.

    Scenario 2:
    The Runner ID of choice is Noise ("Whenever you install a virus program, the Corp trashes the top card of R&D"). The Runner plays a virus, causing the top card of R&D to be trashed.

    Scenario 3:
    The Runner plays Forged Activation Orders on an ice that the Corp could legally rez, but the Corp player declines to rez it, trashing it instead.

    Scenario 4:
    The Runner plays Forged Activation Orders on an ice that the Corp cannot legally rez, thus forcing the Corp to elect to trash it.

    Normally I do not answer rules questions before a card is released, but I will make an exception for draft cards.

    1. The Runner’s card trashed the ice, so Hostile Infrastructure triggers.

    2, 3 and 4. The Corp is the one trashing the card, so Hostile Infrastructure does not trigger.
  4. IQ + Corporate Shuffle v. Parasite Ruling
    With Parasite hosted on an IQ and only an Anonymous Tip in the corp's hand, would playing the Anonymous Tip trash IQ? Similarly would playing Corporate Shuffle with Parasite on an IQ trash the IQ?
    Yes. There is a moment, between playing the card and before resolving it, that the Corp has no cards in his or her grip.
  5. Ability Classification Ruling
    I'm unclear if the following have constant or conditional abilities:

    Parasite: "Host ice ... is trashed if its strength is 0 or less." Constant ability, or conditional with trigger condition "host ice has strength 0 or less"?

    Inside Job: "Bypass the first piece of ice encountered during this run." Constant ability, or conditional with trigger condition "when you encounter the first piece of ice during this run"?

    Chum: "Do 3 net damage unless the Runner breaks all subroutines on that piece of ice." Constant ability, or conditional with trigger condition "when a subroutine resolves during the encounter with the next piece of ice, or when the encounter with the next piece of ice ends, or when the run ends during an encounter with the next piece of ice."

    Dirty Laundry: "After the run is completed, gain 5 if it was successful." Constant ability, or conditional ability with trigger condition "the run ends."
    Parasite: “Host ice has -1 strength” is a constant ability.

    Inside Job: Constant ability.

    Chum: Constant ability.

    Dirty Laundry: Conditional ability that resolves when the run ends.
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