Conjure Elder Elemental

After sacrificing a elemental ( fire, water, earth, or air) you call forth an elder elemental servant.  An elemental of the same element as the one you sacrificed with an challenge rating 16 or higher  appropriate to the area you chose appears in an unoccupied space within 10 feet of it. For example, a fire elemental is sacrificed and a Phoenix is summoned, or  an earth elemental is sacrificed a Zaratan is summoned . The elemental disappears when it drops to 0 hit points or when the spell ends.

The elemental is friendly to you and your companions for the duration. Roll initiative for the elemental, which has its own turns. It obeys any verbal commands that you issue to it (no action required by you). If you don't issue any commands to the elemental, it defends itself from hostile creatures but otherwise takes no actions.

If your concentration is broken, the elemental doesn't disappear. Instead, you lose control of the elemental, it becomes hostile toward you and your companions, and it might attack. An uncontrolled elemental can't be dismissed by you, and it disappears 1 hour after you summoned it.

The DM has the elemental's statistics. Sample elementals can be found below.

At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, the challenge rating increases by 1 for each slot level above 7th.

Sample Elementals