Spectrum Monsters (スペクトラムモンスター (formatted as
Spectrum Monsters are unique in that they require no Material Monsters whatsoever to be Spectrum Summoned. They are instead Summoned using the players' Life Points as the payment, done when the user has a complete Spectrum Wheel.
Spectrum Monsters do not have Levels. Instead, they have Wavelengths.
The name "Spectrum Monsters" derives from the Spectrum Wheel's seven Spectrum Pieces, which are the colors of the rainbow, as well as their rainbow-colored card frames.