The over-sized blackberry is called an "mbira," or more colloquially an African Thumb Piano.

Tags for this video have been changed from 'mouth trumpet, beatbox, cool dude, kalimba, thumb piano' to 'mouth trumpet, beatbox, cool dude, kalimba, thumb piano, mbira' - edited by dystopianfuturetoday

^ i think the mbira body is rounded and made with a gourd, whereas the kalimba is the more standard box shape and is made with wood. i could be wrong, but i once looked this specific query up in my younger, more curious days.

I've always heard of the thumb piano referred to as an mbira.