2018-03-16 : If Ruric Thar can’t attack for any reason (such as being tapped or having come under that player’s control that turn), then it doesn’t attack. If there’s a cost associated with having a creature attack, the player isn’t forced to pay that cost, so Ruric Thar doesn’t have to attack in that case either.

2018-03-16 : Ruric Thar’s triggered ability resolves before the spell that causes it to trigger. The ability will resolve even if that spell is countered.

2018-03-16 : Ruric Thar’s triggered ability triggers whenever any player casts a noncreature spell, including you.