Horvath's Staff (originally known as Horvath's Sword and also known as Horvath's Cane) is a magical cane belonging to the evil sorcerer Maxim Horvath.
Originally, it was once Horvath's magical sword which at one point in the past, Horvath turned it into the staff using his magic in order to suit it with the modern era, and presumably, to avoid unwanted attention. Horvath uses his staff for all of his magical skills in the same manner with how sorcerers in other fiction use their staves/wands, including while fighting Balthazar, his former best friend.
Originally, it was a long, medieval sword with the blue crystal on its pommel that glows whenever Horvath use his magic. After Horvath changed its form to suit the modern day era, it became a long and black cane, which retains both its blue crystal and the crystal's glow every time Horvath uses his magic.
Powers and Abilities
Horvath's cane enables Horvath to use his magic in the same or similar manner with sorcerers whom uses their rings. Before being modified, its powers were in standard magical level, presumably in same level with Balthazar's ring. Horvath later amplifies its magic by attaching Merlin's ring (by stealing it from Dave Stutler), Drake's ring and Abigail's Necklace on it. In process, the staff became very powerful, and ultimately amplifies Horvath's own magical skills.
However, like magicians in fantasy works who uses magic via wands/staves, Horvath's Staff was the only known means for him to use his magic. If he is separated from his staff, Horvath became a vulnearable target until he retrieves his staff. This was shown when Dave uses his machines that blasts Horvath's cane away, disarming him and allowed Balthazar to blast him.