Takao's face puffs up, not unlike the keychain, Midorima knows that face and as they walk from the store the point guard goes into a fit of the snickering. Oh this best friend of his, always interesting.

"That thing is so ugly it's almost cute." And of course, it had potential as a lucky item so he bought it, he simply wouldn't be Midorima if he didn't. Had he paid better attention and seen exactly it looked like, he would have known, still would have teased though.