You mean the Stitch collab event? She wears short pants and a shirt exactly the same as Grim's, but the shirt is styled like Riddle and more revealing both her cleavage and belly. She also wears some accessories and a hat similar to Ace's.

The boys' opinion? Floyd was very cool about it and just thinks it's cool. Lilia was the only one who complimented Yuu genuinely. Riddle, Azul, and Jack were flustered so bad and Riddle complained to her to cover up. Ace was like, "Looking good, Yuu! If Deuce was here, he would faint immediately."