Stitch has been known to dodge plasma fire.  Mary may have taken him unawares with her initial assault but he sees this one coming and dives to the ground. He comes up a moment later, grinning from ear to ear.

"Ha!" Missed! Never mind that he's now covered from head to toe in fresh powder. It's the principle of the thing. He turns; thumb on his bulbous nose, clawed fingers waggling. And his eyes go wide as Mary's destination becomes clear.