Does Singularity's "up to 2" units mean 0-2 or 1-2 units? Can it target 0 units?

Ruling: "Up to 2" means 0-2 units, so you can choose to target 0 units with Singularity.

Nuances:

• This matters when the opponent has no units, allowing you to avoid killing your own units
• If an opponent steals the spell, they can also choose to target nothing with it