Brand

You speak a command to a creature after you make a melee attack . The target must succeed on a constitution saving throw or follow the command at the guven time or when specified. The spell has no effect if the target is not humanoid.

You are able to tell the branded creature(s) to do certain actions such as taking an item, killing something, etc. 

You can also kill the branded creature instantly making its head explode healing you 5d6 health points