Conjure Anomaly

5th-level conjuration
Casting Time: 1 minute
Range: 90 feet
Components: V, S, M (an aberration component)
Duration: Concentration, up to 1 hour
Class: Warlock, Wizard

You call forth an aberration at random from the Anomalies, a distant and bizarre plane. Choose an unoccupied space within range. An aberration of challenge rating 5 or lower (GM’s choice) appears in the space. The aberration disappears when it drops to 0 hit points or when the spell ends.

The aberration is friendly to you and your companions for the duration. Roll initiative for the aberration, 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 aberration, it defends itself from hostile creatures, but otherwise takes no actions.

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

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the challenge rating increases by 1 for each slot level above 5th.

Source: Heliana's Guide to Monster Hunting