A Viral Unlockable is a piece of Unlockable Content
such as an achievement, skin, or weapon, that is earned by playing with another player who has already unlocked it. Depending on the game, merely meeting such a player may be enough, or you might have to defeat (or be defeated by
) the player in question.
Because of the obvious Catch-22 Dilemma
involved with this trope, someone
has to get it some other way so they can spread it to normal players
. Methods includes time-limited events, an alternate (often much more difficult) unlocking method, or some people (usually staff members) being given it immediately.
A type of Socialization Bonus
, and possibly a Luck-Based Mission
First Person Shooter
- In Super Smash Bros.: Brawl, playing online against a secret character unlocks that character instantly.
Multiplayer Online Battle Arena
- Team Fortress 2:
- The Pyrovision goggles can be earned by dominating a player who was wearing them. Seeding was done by just giving a pair to anyone who launched the game in a limited time.
- The infamous Ghastly Gibus. Again earned by dominating someone wearing the hat. Seeded by a semi secret webpage.
- Some title cards in the Call of Duty series are unlocked in this manner. For example, the "STD" and "Infected" titles in Call of Duty: Modern Warfare 2 and 3 are earned by using your knife to kill someone who has the title equipped.
- Brütal Legend has the "Six Degrees of Schafer" achievement, which can only be obtained by playing an online game against someone who already has it (with the original vector being, of course, Tim Schafer).
- The post-game DLC quests for Dragon Quest IX have become this since the DS' Wifi Connection servers were disabled- the quests can still be unlocked via local wireless connection with a player who already has them, making them one of the few bits of DS DLC that can still be legitimately obtained post-shutdown.
- In Pokémon OmegaRuby and AlphaSapphire, the Eon Ticket item (allowing the owner to battle Latias or Latios depending on version) was distributed via StreetPass, meaning that getting it required you to be near someone else who had the Ticket and who had their 3DS with them. This made getting it fairly easy in populated areas, but very difficult for players who were more isolated.
- XCOM: Enemy Unknown has an achievement named "Bubonic", which can only be earned by playing online against someone who already has it.
- In Dragon Cave:
- The Tinsel and Shimmer-scale breeds are only available as contest prizes or having it bred. For a long time all Tinsels and Shimmer-scales on the site were descended from the 5 gold/10 silver/15 bronze Tinsels and 10 gold/20 silver/30 bronze Shimmer-scales given to the original winners of their respective contests, but they have since been made much more obtainable (e.g. monthly raffle).
- For Valentine's Day, Halloween, and Christmas, there's a new limited-time release each year that drops only for 24-72 hours depending on the event. The only way to obtain these breeds in subsequent years is to get one that was bred by another user.
- The concept of an Erdos number. Mathematician Paul Erdos had a number of 0. Anybody who has worked directly with him is given the number 1. Working with somebody who has an Erdos number of 1 grants one the Erdos number 2, and so on. In a similar vein, the concept of Bacon Numbers calculates the distance between an actor and Kevin Bacon,