Clarence quickly hid in a nearby supply closet when Robin called it out. At the first sign of fighting he came out and saw that Supergirl had handled it. "Good job." He said to her. "Now let's keep moving." He said enthusiastically. He looked at the group, 'Yeah, Robin, Kid Flash, and Supergirl... Defiantly a test.' But, he wanted to keep it to himself just in case, that well, it was part of the test too? "Mr. Wayne is going to be paying a pretty penny for that." He said whistling as he walked by the damage his magic-gone-wrong had caused. 

 "Biggest league benefactor, hope that doesn't change." He mused to himself, Batman would have his head... Figuratively speaking of course.