Savage Colosseum + messenger of peace

savage colosseum wrote:If a monster attacks, its controller gains 300 Life Points at the end of the Damage Step. All monsters must attack, if able. During the End Phase, destroy all face-up Attack Position monsters the turn player controls, that did not declare an attack.

messenger of peace wrote:Neither player can declare attacks with face-up monsters that have 1500 or more ATK. During each of your Standby Phases, pay 100 Life Points or destroy this card

After an attack has been declared, if the attack is stopped but not negated by an effect like "Gravity Bind", then the monster is still considered to have declared an attack, so the monster is not destroyed during the End Phase by "Savage Colosseum". However, if the monster's attack is negated by an effect like "Negate Attack", then the monster is not considered to have declared an attack, so the monster is destroyed during the End Phase.[3]

Yoko318 wrote:Since Swift Scarecrow doesn't negate the attack, it would be safe from Colosseum. However, any other monsters would still be destroyed, because the Battle Phase ended before they declared an attack.