There are cut animations to an unused game mechanic that would have allowed players to create their own Bonfires. It was even present in a trailer shown at Gamescom 2015, showing a knight placing a Bonfire sword into a body and igniting it.
The first animation set found in the game's files shows the aforementioned placing of the sword, along with one removing the sword from a body. The second set shows an animation using both hands to insert the sword, then an idle "prayer" animation. In one of the leaked screenshots, this animation is seen with a black fire rising from a body, possibly being absorbed by the player.
It was likely cut due to gameplay balance issues, as it would effectively remove the need to travel an intended path to a specific goal, ie a boss fog gate. It would have also likely created issues with enemies that respawn after sitting at a bonfire.