It apparently hasn't been said yet, but this card is absolutely brutal when paired with Gang Sign. Each time the Corp scores an agenda, you get a two card access from HQ, and that's only with ONE Gang Sign. Multiple signs will trigger in succession, each time granting you two accesses with NAT. The 'cost' of trashing the first trashable card you access each turn is negligible, since you're probably playing Criminal or Anarch and subsequently rolling in dough or scrubbing / imping the Corp anyway, respectively. And you really should be trashing any and all corp cards you can in the first place, if for no other reason than to reduce the odds you'll access the same card(s) again.

Also, it costs 0 and, as WayneMcPain points out, is only three influence. I fully expect to see NAT in a Leela Gang Sign deck.

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But if you're playing gang sign leela you can do the same thing with hq interface without spending influence. —
Or you could do both and get a 5-card HQ access with only one gang sign. —

Mechanically, a strong card, as others have mentioned, and anyone who plays it can attest.

Thematically, it is also a strong card. A virulent Parasite infecting the Corp's ICE? Mmm... Delicious flavor.

Design-wise, it is a curious case of "what were they thinking?" Let me explain.

Most cards with a subtype typically follow a set of rules or principles. Consider current events. All current events have the same 1st line in their text box: "this event is not trashed until an agenda is stolen or another current is played" which makes the current cards distinct from other event types. To give an even more obvious example, the three breaker types all break a specific kind of ice - Killers for Sentries, Decoders for Gates, and Fracters for Barriers. All console cards come with the "console limit" text, and all double events cost an extra click, and the Caissa programs all have a similar "behavior". I could go on and on and on.

But then we come to the virus subtype. What do the virus cards have in common? Virus counters, of course! But wait, no, not all of them. Some, maybe even most, use virus counters, but a few don't follow that rule. Strange. Even more baffling, in my opinion, is that FFG didn't use the "install only on a rezzed piece of ICE" as the defining ability of virus cards - an ability that only makes sense the more you think about it. Why would I be installing viruses in my rig? I wouldn't, but I would be infecting the Corp systems, for sure. Also, how does the Corp wipe viruses off of my PC? Purging viruses leeching off of their ICE is one thing, but did they some how hack my comp and start deleting my viruses? Oh, the confusion.

Parasite presents a "what could have been" that will always make me sigh. I can tolerate broken cards and "useless" cards (fortunately A:NR has very, very few) but design inconsistency kills me. I will continue to play Parasite and all the rest, but I do so with a heavy heart.

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So, this isn't much of a review of Parasite... —
For what I've been told, in the original Netrunner, virus token where given to the Corp player, so the purge made sense with that. Now, for the sake of simplicity I guess, Runner player keeps the virus counter on his side. Just imagine that virus programs are remote program growing on Corp's network, but with control on the Runner's rig (hence the use of MU). —
Yes. —
Every card with the virus subtype is hurt by the Corp three click cost ability purge virus counters, which seems like a pretty clear design delineation to me. To thematically explain the functionality, I like Lupus's description. —
Lupus's rational for the flavor is pretty solid. Well played, sir. —
Parasite on the NAPD Most Wanted / 02.01.2016 —

Part of a cycle of stealth chips, the other two being Dyson's Fractal Generator and Mac's Lockpick, they are not terrible economic choices, paying for itself after one use and saving you real credits in the long haul. Obviously they are most effective when used in conjunction with the stealth breakers BlacKat, Dagger, Refractor, and Switchblade. The stealth chips are also high on influence, limiting the potential ease with which a 'pure stealth' deck can function, as importing them leaves precious influence to spare, which is a good thing in my opinion. As a two-of in a standard criminal deck that wants some support for its killer of choice, Silencer helps.

The art, however, leaves me disappointed. DFG and Lockpick both depict a close up of the chips in all their glory. DFG in particular has some amazing artwork, reminiscent of LLDS Processor. But here we have Gabe, holding up what looks like a tiny revolver-shaped chip, backed by some conspicuous holo-grid as he eye-balls it hungrily. Sorry, but I'm not feeling it. As cool as Gabe is, this artwork doesn't do him justice - much less the Silencer - which is a shame, doubly so considering Studio Gong did LLDSP and DFG.

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The art is especially disappointing when the flavour text is this good - sure, the other two are more personal, but this shows what hardware can really mean in the Android world —

The two other reviews here (Accalion's and Andrew's) both sum up MaxX nicely. They also view her from two different perspectives - a nice bonus for a moderate 'drawback'; or, as an enabler for recursion, respectively. And most people seem to view her ability in one of those two ways, and that's fine. But I'm under the impression that the designers had something different in mind...

Consider her flavor. She's a punk rocker. She likes her music fast and loud, heavy and dirty. In her art she's giving the "two-fingered salute", an insulting gesture in some parts of the world, used to indicate contempt and/or defiance particularly for authority figures. She has 'Riot' on her shirt, (a green shirt, mind you) and a utility belt including some PADs and other hardware. She also has one of the most beautiful lines of flavor-text in any game: "Fuck you, motherfucker!"

Brilliant, but what does it all mean? It means MaxX doesn't give a fuck. She has no sympathy, no remorse, and neither should you. And therein lies the key to understanding her ability. The first part is a red herring. It isn't important. It doesn't matter. Who cares if you trashed all that cool stuff? Not MaxX, so fuck it. Draw your card and run.

MaxX is intense. There is no more accurate word for her. 'In tense'. She lives in the moment, for the moment. Her lifestyle is detrimental to her in the long term. So what? YOLO. Blaze it. Fuck all that career planning and late-game retirement bullshit. It's time to make some noise.

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She's in tents! —