Ralph and Caitlin in “Unfinished Business”

Ralph

I've seen enough episodes of Sister, Sister to recognize a siblings' spat when I see one.

Caitlin

So, I'm trying to help Cisco with his metahuman cure, but every time I start working on it, Killer Frost takes over and messes with my equations. [points to a whiteboard] Like this. She changed all my heterozygotes into asterisks.

Ralph

Oh. I thought those were just tiny snowflakes. So she's not on board?

Caitlin

No. And I don't know exactly know why.

Ralph

Can't you just ask her?

Caitlin

Oh, I've tried. But every time we start talking about it, she starts singing Barney's "I Love You" song.

Ralph

Ooo, that's cold.