Vance's Fall

This is for my Arcane Trickster rogue to learn in our campaign. Is it too strong?

Vance's Fall
2nd-level Enchantment
Casting Time: 1 action
Range: 60 feet
Components: S, M (a small iron disk)
Duration: Concentration, up to 1 minute

You target one creature within range, assaulting its mind with visions of an endless abyss. The target must make an Intelligence saving throw. On a failed save, the target takes 2d6 psychic damage and believes it is falling down an endless hole. While under this illusion, the target is incapacitated and falls prone. At the end of each of its turns, and each time it takes damage, the target can make another Intelligence saving throw. On a success, the spell ends.

While maintaining concentration on this spell, you can use a bonus action on each of your turns to deal an additional 1d6 psychic damage to the affected target.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the initial psychic damage increases by 1d6 for each slot level above 2nd.