Can you respond to a unit being played, and how does the chain work when a unit is played?

Ruling: Units immediately resolve when they're finalized onto the chain, so you cannot respond to the unit being played itself. Any "when I'm played" triggers will go on the chain with the unit already in play.

Sequence:

• Unit is finalized onto the chain
• Unit immediately resolves and enters play
• Any "when I'm played" triggers then go on the chain (with the unit already in play)

Nuances:

• Units behave differently from spells, which linger on the chain before resolving