A watermelon
Looks green on the outside, but once you cut it, it’s all red and juicy, and sometimes it’s got a bunch of weird stuff inside.
That guy is green on the outside, but he’s a total red flag on the inside.
She’s all eco-friendly, but she’s the one who let the trash pile up.
He’s kind, but he’s got a mean streak, like a watermelon with a secret.