Flip monsters (Japanese: リバースモンスター Ribāsumonsutā "Reverse Monster"), formerly Flip Effect Monsters (リバース効（こう）果（か）モンスター Ribāsu Kōka Monsutā "Reverse Effect Monster"), are Effect Monsters with the ability "Flip". They all have a Flip effect, although they may also have other effects in addition to their Flip effect. Flip monsters usually have a low Level, and often have low ATK and DEF. The "Charmer", "Krawler", "Prediction Princess", "Shaddoll", "Subterror", and "Worm" archetypes are primarily based on Flip monsters. Flip monsters can also be Tuner monsters or Pendulum Monsters.