Can Fox Fire be played with 0 targets when it says 'any number'?

Ruling: Yes, Fox Fire can be played with 0 targets. "Any number" includes 0 as a valid choice.

Nuances:

• Cards that allow 0 targets are typically worded with "up to" but "any number" is functionally the same
• Playing it with 0 targets can be useful for triggering effects like Ravenbloom Student
• When adding up 0 targets' Mights, you get 0, which satisfies the "4 or less" condition