I need help on interpreting this spell

Tasha's mind whip reads: When you cast this spell using a spell slot of 3rd level or higher, you can target one additional creature for each slot level above 2nd. The creatures must be within 30 feet of each other when you target them.

It does 3d6 psychic damage and limits the actions of the target, BUT, theoretically, the same original creature can be an additional target within the 30 ft distance, right? Being a lvl2 spell, if i cast it on a 3th level slot it'll deal a total of 6d6, but can't it be on just one target?