Sei grabbed for the more age-appropriate clothing in a box to the side: jeans and boxer shorts. Jonathan, angry at the humiliation and not thinking too clearly as he regressed, shoved his arm at the last moment, and before Sei realized what had happened, he was clutching a plush Barney doll.
Sei dropped it instantly as if it were burning hot, but from the expression on Jonathan's face, he could see the harm was already done.