A: "Knuckles, you're a rock star." It’s a visual pun. Knuckles is made of rock-like skin, and he sings. You can't say "Ngôi sao nhạc đá" because it loses the rock/mineral joke. We settled on "Knuckles, cậu đúng là ngôi sao đá ," using "đá" to mean both "stone" and a verb for "to kick" (implying awesomeness). It’s a stretch, but fans liked it.