Final answer:
Cadence's Granddad reminds her of 'The Little Mermaid' when he interrupts her kiss with Gat, alluding to themes of love and transformation.
Step-by-step explanation:
When Cadence's Granddad interrupts her kiss with Gat in the attic, Granddad reminds Cadence of The Little Mermaid. This is a reference to a well-known fairy tale written by Hans Christian Andersen, which features themes of love, sacrifice, and transformation. The Granddad probably evokes this story to highlight a romantic or transformative moment that is happening in Cadence's life, much like how the mermaid in the tale experiences profound changes because of her love.