This is Mareto. He is 2 months old and lives in Japan.
自分のおならの音にびっくりするわが子。
Mareto's father, Hirohito, tweeted this video, saying, "My son is surprised by the sound of his own fart."
Here he is smiling up at his mother...
When all of a sudden, he surprises himself with a fart.
Hirohito told BuzzFeed News it was a miracle that Mareto's reaction was caught on video.
He said Mareto's mother Eri just happened to be filming and couldn't help but burst out laughing when it happened.
Hirohito said Mareto is a very friendly baby and looks like both his mum and dad.
He said that they are both amazed at how quickly their son is growing up.
希仁だいぶ太ったな〜！😳
"Mareto has become so chubby!"
The couple have shared many adorable photos of Mareto on social media.
すごいご機嫌☺️！
"He's in such a good mood."
初スイマーバ😂💕 泳ぐ姿がたまらんかったwww 一人でプカプカ泳ぎよんしゃった😭❤️
"His first time using a Swimava. The way he looks when swimming is so irresistible lol. He was swimming and floating all by himself."
エミフル広すぎでわからん！😑
"The shopping mall is so huge!"