Trapped in the fight

Everytime a creature with power 5 or higher deals damage, it deals 3 damage to all creatures with
power 3 or less. If any creature is destroyed by
this effect, it cannot be regenerated or leave the graveyard.
If two or more creatures with power 6 or more
fight,destroy all creatures with power 4 or less,
these can't be regenerated or leave the graveyard.