Abomination

Scheußlichkeit

Whenever this creature blocks or becomes blocked by a green or white creature, destroy that creature at end of combat.

Renaissance

Fourth Edition Foreign Black Border

Fourth Edition

At the end of combat, destroy all green and white creatures blocking or blocked by Abomination.

Legends

All green or white creatures blocking or blocked by Abomination are destroyed at the end of combat.

The color of the blocking/blocked creature is checked only at declaration of the block. If the creature is green or white at that time, it will be destroyed at end of combat even if it changes color before combat ends.