I am unsure how the following situation resolves:
Player A attacks Player B with a Two-Headed Cerberus with a Baleful Eidolon bestowed upon it, making it effectively a 2/3 with double strike and deathtouch. Player B blocks with a Nessian Asp.
The first strike damage will kill Player B's asp, so he regenerates it using Boon of Erebos.
What happens in the next damage phase? I can see three possibilities:
- Both creatures die (the Asp is killed by the deathtouch, the Cerberus by damage)
- Neither creature dies because the regeneration removed the Asp from combat, but the Cerberus was still effectively blocked and does not hit Player B.
- Neither creature dies, but the Cerberus is not blocked in the second damage phase (I don't think this makes sense) and so hits Player B for 2 damage