She might have been concentrating on what was below her, but Diana was far too much of a warrior to not be aware of her back. She heard a faint whine, and turned her head just slightly to pinpoint it; it resolved into a whooshing sound as the rockets engaged. Oh, she knew that sound all too well.
In a blur, she flew up off the roof, the rockets trailing her, and turned to engage them. They were too small to be any kind of nuclear head, she saw instantly, and the insignia...
Was that a smiley face?
She flew up high enough in the atmosphere that they wouldn't directly affect the city in case it was a sort of gas, then turned to face them. Both hit her bracelets squarely, knocking her back and covering her with foam.
No, not foam. Whipped cream.
Diana hovered there a moment, completely perplexed, brushing some of the cream off her uniform. Remnants of a smiley face clung to the sticky side of her bracelet now, and she peeled it off to look at it. The Joker here didn't use this type of technology, at least not yet. If it had been some kind of toxin, she would have guessed Crane perhaps. But no, it was harmless. And it was targeted right at her. By someone that probably knew she was capable of withstanding bombs that would take out just about anyone else. Yet that wasn't the point, was it?
In the end, the smiley faces gave it away, because they had a certain manga-style look. Glaring, like a mother would towards a recalitrant child, Diana said, "Toyman! Show yourself, Hiro." After a second, she added, with a roll of her eyes, "I promise I won't be mad." After all, he was one of Cassie's friends. Wonder Girl would probably be rather put out with Diana if she beat the boy up for a prank.