The ghost is a neutral creature in Heroes of Might and Magic II that can be trained from the barrow mounds. While they are decent fighters, their biggest strength is their ability to boost their numbers: any creature they kill in combat, turns into a ghost and is added to the stack. Any weak creatures in the army will quickly be added to their forces - peasants are especially vulnerable to this. When facing them, try leaving the low-level creatures with another hero, and only use fifth- or sixth-level creatures.