Back to the OP, it should be noted that the automatic 5d10 psychic damage by itself is already quite good. Its better damage than magic missile (the other auto damage spell), and psychic I would say is close to force in how little resistance you normally have against it.

Second, as an Int save...the chance of getting this on a monster is nigh automatic in many cases. Especially your melee oriented ones where restrained can be a harsh condition.

Even without the movement clause, there are a lot of monsters where your choice is:

1) Stand there and do nothing (because your restrained and can't move into melee).
2) Take 10d6 damage and move on with your life.

A lot of DMs will take option 2 simply because better that the monster does something.

So my assessment is that this spell is clearly top tier for its level for damage. That said, I don't know if its power creep or correction. I have generally found the damage 6th level spells to be lackluster. But it clearly blows disintegrate out of the water.

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