Can you react to units being played, and if so, does the unit hit the field before you can react?

Ruling: Playing a unit opens a chain, but it resolves immediately and nobody gains priority, so you cannot react to units being played.

Nuances:

• This rule applies even though playing a card creates a chain
• Units are considered played only after they've finished resolving and are on the battlefield
• Triggers that check for "played" events happen after the card has resolved and is on the battlefield
• A unit with a "Play" ability will see itself being played because it's already on the battlefield when the trigger checks