What happens when a Command spell (and others) is returned by a Ring of Spell Turning?

Question

A cleric casts a Command spell targeting you, specifying the Flee option. You have a Ring of Spell Turning and you get a 20 for the save, so the spell is returned. We are going to assume that the cleric fails his save.

• The spell is returned but, can you specify other option for the spell (halt, approach, etc.) ?

• From where the cleric will flee? From his original position, from you, from the ring, from himself?

• In case the spell was cast using a higher level (affecting a second creature), could be the spell be returned?

• Extra: In case the returned spell had concentration or a dismiss option. Could the original caster finish the spell ending the concentration or using the appropriate action to end the effect? When could he finish the concentration?

Answer 1

The Ring of Spell Turning states:

In addition, if you roll a 20 for the save and the spell is 7th level or lower, the spell has no effect on you and instead targets the caster, using the slot level, spell save DC, attack bonus, and spellcasting ability of the caster.

So this means, the spell does not originate from you even when you have returned it, but instead you merely redirect the target. This means that it is as if the cleric used command on themselves using the word "Flee."

This is the effect of the "Flee" command word:

Flee. The target spends its turn moving away from you by the fastest available means.

Therefore, the cleric is commanding themselves to flee from themselves. This is a contradiction -- you cannot possibly move away from yourself. However, the command spell also stipulates:

If the target can't follow your command, the spell ends.

So in this case, the spell would end immediately, since the cleric cannot follow their own command.

This also means that if the spell had a concentration requirement, such as polymorph or banishment, they can willingly end concentration because it is still their spell, they just shot themselves with it instead of you.

Finally, the Ring of Spell Turning cannot return a spell that does not target only you. If command was cast at a higher level such that it targets you and someone else, then you cannot return it. You would also not have advantage on the saving throw.

Answer 2

The original caster will flee.

Here's the Ring of Spell Turning: (DMG, p.193):

While wearing this ring, you have advantage on saving throws against any spell that targets only you (not in an area of effect). In addition, if you roll a 20 for the save and the spell is 7th level or lower, the spell has no effect on you and instead targets the caster, using the slot level, spell save DC, attack bonus, and spellcasting ability of the caster.

Addressing your sub-questions:

Can you specify another option for the spell (halt, approach, etc.)?

No. The target of the spell has changed, nothing else. The wearer of the Ring doesn't control anything about the spell.

From where will the cleric flee?

The Flee option on command is:

The target spends its turn moving away from you by the fastest available means.

Since the new target and "you" (the caster) are now the same person, technically the cleric would spend their next turn fleeing from themselves. It's up to the DM to decide what that means; having them flee randomly or from the original spell's targets seem to be reasonable options, as is declaring that the command can't be obeyed, and thus has no effect.

In case the spell was cast using a higher level (affecting a second creature), could be the spell be returned?

No; the Ring of Spell Turning affects spells that have only the wearer as a target, and none others. It would have no effect at all against command cast on multiple targets (not even advantage on the saving throw).

Suppose the returned spell required concentration or had a dismiss option. Could the original caster finish the spell by ending concentration or using the appropriate action to end the effect? When could they do this?

Yes, they are still the caster, so they can end concentration on the spell or take an action (if applicable) to end it. Technically concentration can be dropped at any time, but most DMs would probably not allow this until after the initial effect of the spell had resolved. If an action is required to end the spell, then the caster follows whatever rules are specified in the spell description.