So his pet is looking for a weapon. Not very effectively, to be sure. Wei Wuxian takes the flute, giving it a twirl between his fingers. "What, you don't like music?"

He lets the leash drop so that he has both hands to play, and lifts the flute to his lips, starting a sad, lonely tune about death and mourning.

Lan Zhan brought him the flute, after all, so it only makes sense to play, but even with this entertainment he's in no mood for happy songs from long ago.