Can Singularity target the same unit twice to deal 12 damage, or must it target two different units?

Ruling: Singularity must target two different units (or just one unit). You cannot target the same unit twice to deal 12 damage.

Nuances:

• "Up to two units" means you can cast it targeting only one unit if needed
• Targeting one unit deals only 6 damage to that unit, not 12