Amduscias governs twenty-nine legions. His true form is as a unicorn, but appears as human form when summoned. He will give concerts if commanded, & is accompanied by the sound of trumpets and other musical instruments. Trees also bend to his command.

Pseudomonarchia daemonum – Johann Wier (1583) (quoted)
Amduscias a great and a strong duke, he commeth foorth as an unicorne, when he standeth before his maister in humane shape, being commanded, he easilie bringeth to passe, that trumpets and all musicall instruments may be heard and not seene, and also that trees shall bend and incline, according to the conjurors will, he is excellent among familiars, and hath nine and twentie legions.
Goetia – S. L. MacGregor Mathers (1904) (quoted)

Amdusias’ Goetic seal

 
The Sixty-seventh Spirit is Amdusias, or Amdukias. He is a Duke Great and Strong, appearing at first like a Unicorn, but at the request of the Exorcist he standeth before him in Human Shape, causing Trumpets, and all manner of Musical Instruments to be heard, but not soon or immediately. Also he can cause Trees to bend and incline according to the Exorcist’s Will. He giveth Excellent Familiars. He governeth 29 Legions of Spirits. And his Seal is this, etc.