Brent gave the piano a disapproving glare as it ding-cling-bong'ed in response to him pressing the keys. What exactly had happened to this thing? It looked like somebody had left it outside in the middle of the last Wizarding War then brought it in the shack to live out the remainder of its days. He especially eyed the three keys that didn't make any noise at all. Seemed like parts of the instrument had already lived out the remainder of its days.

...and then an entirely new sound came out the lid of the piano, causing Brent to take a quick step backward and draw his wand. Nothing other than a sound alone had come out of the piano, but there was clearly someone or something was inside of it. Great. Just what he wanted to do--lift up the lid of the piano and get a random surprise. He decided to not be so hasty but to instead explore the rest of the piano first. Maybe he could see a little of whatever it was that had made that sound.

With a wave of his wand, Brent produced a Sliver Shield Spell for added protection, and then he followed that up with "Fianto Duri!" It occurred to him that this was the second time he'd used that exact combination of spells in this challenge alone. It was a very useful combination, though, he thought. The first part gave him a shield, while the second part would allow him to still explore the piano without having to give his undivided attention to keeping the shield in place. So with the confidence that whatever was inside the piano would have at least a hard time getting to him, he circled around to the side of the piano and glanced underneath it. Still walking around it, he explored the back and then the other side. His fingers poked around in various places while still trying to figure out what had made that sound.

Finally, he was left with no other idea than to life up the lid. First, he wanted to try a few spells; after all, he wasn't in too big of a hurry for random surprises. "Homenum Revelio!" he said, and then it occurred to him that he just might be a tad freaked out if a random human presence was revealed to him. Although, it eventually wouldn't surprise him at all if that was the case, seeing as the first challenge had ended much in the same way. He hadn't forgotten Gerald, the poor, elderly, unsuspecting Muggle that had turned out to be nothing more than a dummy. He followed the first incantation with "SpeRevelio!" The spell hadn't been too successful from what he'd always been taught, but just on the off-chance this was his lucky day, he wanted to see if anything secretive would be revealed to him.

So with a Silver-Shield Spell, Fianto Duri, and two revealing spells in place, he leaned over and quickly pulled up the lid of the piano.

Alright, hit me with your best shot.

...

On second thought, don't actually hit me...

He did, however, press the keys once again, particularly the three that had made no noise at all. Something was the cause of that silence, after all.