Choose a willing creature that you can see within range.The target swells in size and grows an extra pair of long, thin arms from its shoulders. Until the spell ends, the target has advantage on Strength checks and Strength saving throws, advantage on Intimidation checks, and gains the Many-Armed Fighting Style detailed below. While under the effects of this spell, the target can use two-weapon fighting even if the weapons they are wielding are not light, even if those weapons are heavy.

When the spell ends, the target can't move or take actions until after its next turn, as a wave of lethargy sweeps over it.

At Higher Levels. When you cast this spell using a spell slot of 5th or 6th level, the target can additionally add their ability modifier to the damage of their first bonus attack. When you cast this spell using a spell slot of 7th or 8th level, the target additionally can add their ability modifier to the damage of all bonus attacks. When you cast this spell using a spell slot of 9th level, the target additionally gains a bonus to all of their attack and damage rolls equal to your spellcasting ability modifier.

Many-Armed Fighting Style
When you use a bonus action to engage in two-weapon fighting, you can choose to gain disadvantage on the attack granted by two-weapon fighting. If you do, you can make additional attacks as part of the bonus action. If you are wielding at least 3 weapons, you can make an additional attack as part of two-weapon fighting using a weapon you have not used in either your attack action or the first attack of two-weapon fighting. If you are wielding 4 weapons, you can make another additional attack as part of two-weapon fighting using a weapon you have not used in either your attack action or the previous two-weapon fighting attacks. Any additional attacks you make as part of this bonus action also have disadvantage. You don’t add your ability modifier to the damage with the third and fourth attacks unless it is negative.

If you are wielding melee weapons in at least three hands, you can use your reaction to parry a melee attack that would hit you. You add 2 to your AC against that attack, or 3 if you have melee weapons in four hands, which can make the attack miss.