So this animation starts a bit late into the part of the stream (understandably so, even a second of animation is hard and a lot of work). Backstory a bit that she tells during that stream: Calli ordered a kazoo, however she didn't know how to play it, she was basically blowing into it hard and it didn't make any sound. She figured the inside part was broken or something so she ordered another one. That one also doesn't work for her and she orders a third one (this is the one she mentions in the animation), but before it arrives she has a stream and talks about her struggles with them. A chatter mentions she should hum into it and hilarity ensues. Also the meme you mentioned is just called Kazoo kid. It was a pretty funny meme and if you ever decide you can look up the original video it came from. It's worth it.
So this animation starts a bit late into the part of the stream (understandably so, even a second of animation is hard and a lot of work). Backstory a bit that she tells during that stream: Calli ordered a kazoo, however she didn't know how to play it, she was basically blowing into it hard and it didn't make any sound. She figured the inside part was broken or something so she ordered another one. That one also doesn't work for her and she orders a third one (this is the one she mentions in the animation), but before it arrives she has a stream and talks about her struggles with them. A chatter mentions she should hum into it and hilarity ensues. Also the meme you mentioned is just called Kazoo kid. It was a pretty funny meme and if you ever decide you can look up the original video it came from. It's worth it.
to be fair of all the instruments I have used, I have never played a kazoo. XD