Conjure Elemental, Earth

When a druid casts a conjure earth elemental spell, he or she summons an earth elemental of 16 hit dice to do the druid’s bidding. 

Furthermore, the druid need but command it, and then do as he or she desires, for the elemental does not regard the druid who conjured it with enmity. 

The elemental remains until the time elapses or it is destroyed, dispelled, or sent away by dismissal. Additionally, a holy/unholy word will send the creature back to its own plane.