Am very new to this game - but I love it ! Question is:

After you attach a (Core Set) Forest Snare to an enemy, when does it expire/ get discarded ? There is no text on the card stating how or when it expires which makes it look permanent but that doesn't seem right.

It is indeed permanent. It is a very powerful card offset by the fact that it cost 3 lore resources and has to go on an enemy already engaged with you (meaning it likely got to attack you at least once) and that enemy can't have the "no attachments" or "immune to player card effects" keywords.

Thanks, SGF -- but wouldn't it be OK to attach it to the enemy in the Player action window after it is engaged but before it actually attacks?

Thanks, SGF -- but wouldn't it be OK to attach it to the enemy in the Player action window after it is engaged but before it actually attacks?

Nope. You can only play attachments and allies during the Planning Phase.

Thanks, SGF -- but wouldn't it be OK to attach it to the enemy in the Player action window after it is engaged but before it actually attacks?

Great example from the core set is the combination of Son of Arnor and Forest Snare (Leadership+Lore combo is op anyways ) -> In your planning phase you force the effect of Son of Arnor and engage an enemy, on which you can then cast the Forest snare attachment. 6 resources well spent, for the worst enemies I'd say it's worth it.

That is a costly combo, but can be very useful for snaring a particularly nasty opponent.

a.k.a Hill Troll

Don't forget to give a shadow card to any enemy with a Forest snare attached; even if the enemy doesn't attacks, he still gets it's shadow card... that just gets discarded.