Neighing the active effect of Special Delivery in unstable unicorns
No, this does not count as &quot;playing&quot; a card.
From the rules:

Play vs. Bring Directly into Your Stable
&quot;Play&quot; specifically refers to playing a card from your hand
during your Action phase or playing an Instant card at any
time. If you &quot;bring a card directly into your Stable,&quot; you
do not &quot;play&quot; that card. This means that any card that is
brought directly into your Stable cannot be Neigh'd.

Note that there are two print runs, and the earlier version included a different rulebook without this clarification.