Cane of Byrna
"Cane of Byrna
Like the Cane of Somaria, the Cane of Byrna was once used by powerful wizards to combat evil. In the land of Byrna, where this Cane originated from, evil powers attacked from all directions. The Cane was constructed to defend its bearer from all sides. When activated, the Cane of Byrna emits a protective barrier which encircles Link for as long as he has Magic Power. Press the Y Button to activate and deactivate the cane. If attacked by a swarm of enemies, Link should use this Cane until he is safe."
"Link will feel extremely safe when the power of the Cane of Byrna is encircling him. It's great to have extra protection."
The Cane of Byrna is an item that appears in A Link to the Past.
A Link to the Past
The Cane of Byrna protects Link by rapidly spinning around him while harming or defeating most enemies that come into contact with the Cane. The Cane of Byrna drains Link's magic very quickly, so it is advised to use this item sparingly.
The best strategy to get through this cave is to come equipped with the Magic Cape, and turn invisible before walking on the spike pate. Once at the end of the past, Link will find the Cane of Byrna in a treasure chest. Since Link's magic will most likely to drained by now, it is recommended to bring a Green Potion so he can apply the same strategy while getting out of the cave.
Cane of Byrna sprite From A Link to the Past