You use magic and skill to combine at least four corpses of Medium humanoids within range, creating an abomination. You can use the corpses of Small humanoids instead, but you need two for every Medium corpse you replace. At the end of casting, your magic animates the undead abomination you've created. It has the statistics of a flesh golem, except that it doesn't have immunity to lightning damage or the Lightning Absorbtion trait, it is an undead instead of a construct, and it is chaotic evil, because its horrid existence fills it with hatred. (The DM has game statistics for this creature.)

As a bonus action on each of your turns, you can mentally command any creature you animated with this spell if the creature is within 120 feet of you (if you control multiple creatures, you can command any or all of them at the same time, issuing the same command to each one). You decide what action the creature will take and where it will move during its next turn, or you can issue a general command, such as to guard a particular chamber or corridor. If you issue no commands, the creature only defends itself against hostile creatures. Once given an order, the creature continues to follow it until its task is complete. If it goes berserk while under your control, you can choose to make a spellcasting ability check instead of the normal Charisma (Persuasion) check to calm the abomination.

The abomination is under your control for 24 hours, after which it stops obeying any command you have given it. To maintain control of the abomination for another 24 hours, you must cast this spell on the creature before the current 24-hour period ends. This use of the spell reasserts your control over one abomination you animated with this spell rather than animating a new one. When you cast the spell in this way, it requires no material components and its casting time is only 1 minute instead of the normal time.