An Eridium Furnace used to summon Dexiduous. These totems Eat Eridium.
The Eridium Totems are a new use for Eridium in Sir Hammerlock's Big Game Hunt DLC in Borderlands 2.
Put Eridium in each of the four furnaces which will light the four torches at the Dexiduous Summoning Station and then you can pull a lever to summon Dexiduous the Invincible, a new hidden raid boss.
Each Eridium Fire costs 21, 23, 25 or 27 Eridium so you need 96 Eridium to ignite all of them and spawn Dexiduous the Invincible
NOTE: You have to use all the totems in the same session. If you log out or even leave Hunter's Grotto, all the totems will reset and you would have lost your Eridium.
 Eridium Furnace Locations
Click on each entry below for exact locations and screenshots of each Eridium campfire:
First Dexiduous Totem Furnace
Second Dexiduous Totem Furnace
Third Dexiduous Totem Furnace
Fourth Dexiduous Totem Furnace
You can do these in any order. Here are some maps with the locations of all furnaces (Credit goes to poyeasfy from the Gearbox forums)