Yellow Light is one of the few unfought Light Monsters. It appears in the Lunar Sea Spire. Instead of putting up a fight, Steven carries on a conversation with it. It's a distress signal towards Steven, to show that he is their master, but Steven was unable to understand its language.
- When not speaking English, Yellow Light speaks an alien language which appears similar to the "Unown Alphabet" from the Pokémon series.
- When the White Light turns yellow, it speaks to Steven. However, if the player chooses the wrong option while the White Light is in the yellow form, it is known to copy another light's abilities as seen here.
- This does not have a unique attack, but does have a unique feature, as it is able to communicate with Steven when the White Light turns yellow.