Divide the players into a number of equal teams (ideally 5 or more, but does depend on the number of players).

Each team member is the same type of monster.Suggested monster types are: Vampires, Werewolves, Ghosts, Zombies, Skeletons, Ghouls, Frankenstein’s, Accountants etc.

Each player has three lives/flags/tokens representing their type of monster. One is their own ‘life’ the other two are is ‘infections’.

Decide which types of monster infect each other and which ones share a den/lair (base or other defined item within the playing area). Monsters should not really live with the creature it can infect. A ‘head’ monster (leader) is required at each den/lair. The head monster hands out ‘own monster’ infections and stores any captured ones.

So for example if there are 5 teams,
 Vampires, Werewolves can tolerate each other,
 Ghosts and Ghouls can tolerate each other,
 Zombies have no friends

 Vampires infect Ghosts,
 Ghosts infect Zombies,
 Zombies infect Werewolves,
 Werewolves infect Ghouls and
 Ghouls infect Vampires.

Each type of monster can only catch and infect their chosen ‘enemy’. When a monster is caught by its enemy it surrenders its flag/life/token and any tokens from monsters it has previously captured to its captor which is replaced by the ‘infection’ flag/life/token of that capturing species.

Captured species tokens should be returned to the head monster for safe keeping.

The recently infected monster returns to the den of that monster type to pick up its own ‘infections’. The capturing monster must also return to its den for new infections if both of its original infections have been passed on.

If a species is wiped out then the infection rules will need to be changed. There is no natural ending unless one species infects everyone else.