by Faranim
FYI, since this is not in the rulebook but in the FAQ Thread. It's not possible to prevent a summoned monster from attacking. You must either stop the summoner from summoning, or block the summoned creature's attack.This is especially bad against the new Dragon Summoner, since it has Arcane Immunity there is no way to stop its attack. You must block the summoned creatures, reduce their attacks to 0, or take the wounds (or kill the dragon in the ranged phase).
See Re: Official Rules FAQ Thread
A Creature is considered successfully blocked if all of their attacks are successfully blocked
An attack can be successfully blocked by either:
1. Playing enough block points to block the attack
2. Reducing the attack to 0