Okay, this is gonna be one joke I’m gonna have to explain of the bat. For those who want an easy answer, it’s a reference to Kamen Rider Drive and to a justification of the Remember the New Guy trope (namely memory alteration and/or brainwashing being at hand)

Long explaination: Kamen Rider Drive features a villain who is able to alter the memories of people by using threads of ice that weave into their brains, leaving behind a scar in the shape of a snowflake. Swap out snowflake with sun and you get this joke