At around 1:44 of the acoustic cover of Taekwondo by "Walk of the Earth", the musicians play a blowing instrument.
What instrument is this?
Music: Practice & Theory Stack Exchange is a question and answer site for musicians, students, and enthusiasts. It only takes a minute to sign up.Sign up to join this community
The instrument she's miming (not particularly convincingly) at 1.44 is a Kazoo. They both play them at 2.47, when we get a better view of his.
It's a variation on the 'comb and paper' principle. Not so much blown as hummed into. There's a paper or plastic membrane and a resonating chamber. Available in all good music shops at minimal cost.