Groob and Zerb

Groob and Zerb are night roles from One Night Ultimate Alien

Abilities
Groob and Zerb wake with the other Aliens, then wake again together and look for each other.

They are on the Alien team, unless they're both in the game, in which case they are rivals. They win if their rival dies and they stay alive

Strategy

 * If you don't see your rival, use the same strategy as an Alien.
 * Revealing yourself as Zerb or Groob is a bad idea, as it's just as likely to get you lynched.
 * The Villagers might even decide to lynch the both of you, depriving you both of victory
 * Your highest priority is figuring out if you or your rival were swapped.
 * In the meantime, you should play like a regular Alien would. While subtly indicating that your rival started the game as an Alien
 * Claiming you swapped your rival with a suspicious player won't fool your fellow aliens, but may sway a couple of Village votes.
 * Directly accusing your rival might be an OK idea if there are a lot of Informational roles such as the Seer or Psychic
 * Some observant players might be suspicious of 2 players accusing each other but it isn't uncommon for 2 players to accuse each other
 * Playing with a Leader adds another level of complexity and requires you to focus on more then just your rival
 * If a player seems to be strangely defensive of you and your rival, they might be the Leader
 * Since they no longer care about their own life, they now might want to die, The other Aliens want to vote for the Leader in this case, thus you might want to claim you swapped your enemy with the Leader, swaying the votes of Villagers and Aliens

Role Selection

 * Groob and Zerb pushes the game in the Village's favor
 * They work best when there are a lot of switching roles in play, especially the Robber, where they can't be sure that their rival weren't swapped.
 * They also work well with games with a lot of Alien cards as either a buff to the Aliens, or a significant nerf

Trivia

 * According to an image posted in the One Night Ultimate Alien Kickstarter, Groob and Zerb have been enemies for "the greater part of the last millennium" which implies aliens live for at least hundreds of years.