Big Poe Spirit
Big Poe Spirits are the ghostly remains of Big Poes. After defeating a Big Poe, Link has the opportunity to capture its spirit in an Empty Bottle. These spirits have few uses throughout the games they can be obtained in and can only be found in a small amount of specific areas. Nothing is known about their differences from normal Poes, despite the fact that they appear slightly different and obviously are larger.
Ocarina of Time
Ten Big Poes can be found scattered around Hyrule Field in Ocarina of Time. These Poes are part of a side quest pertaining to the Poe Collector on the outskirts of Hyrule Castle Town. After bringing all ten Big Poe Spirits back to him, he rewards Link with an Empty Bottle.
Only two Big Poes reside in Majora's Mask. One of them is found in Ikana Graveyard. On the Final Day, Link can order the Stalchildren to remove a grave where one Big Poe is located. The other is in a small room Beneath the Well. Big Poe Spirits can be bottled and sold at the Curiosity Shop for 200 Rupees. One spirit is required to pass a Gibdo in the well in order to obtain the Mirror Shield.