Inquisitor’s Flail has two abilities that cause the creature equipped by it to both deal and receive twice as much combat damage as it normally would. These two abilities are not triggers and do not use the stack. These abilities are static ones that create a replacement effect when the equipped creature would both receive and deal combat damage (usually this is at the same time).
Normally how this works is pretty easy to work out, however under certain circumstances it can get odd. If a creature equipped by Inquisitor’s Flail is blocked by more than one creature, it does not get to assign twice as much combat damage. The creature’s power is still the same, and that is the amount of damage that the controller of this creature can assign. When combat damage is applied, this amount of damage is doubled. Here are some examples.
Lets assume that an attacking Riot Devils is equipped by the Flail and blocked by two Hovermyrs. The controller of the Riot Devil will then choose a damage order for these two creatures, however as they are the same thing it does not really matter. When combat damage is assigned, the controller of the equipped Riot Devils has only two points of damage to assign, and he must assign it to the first of the two blocking Hovermyrs. He cannot split this damage and assign one to each blocker. When combat damage is dealt (immediately after it is assigned), the Riot Devils will be dealt four points of damage, the first Hovermyr in the blocking order will receive four points of damage, and the other Hovermyr will not be dealt any damage and will survive combat.
The trample ability works much like when creatures ‘gang’ block, except the defending player can also be dealt damage. Let’s assume that a Festerhide Boar with two +/+1 counters on it is equipped by the Inquisitor’s Flail. If this Boar is blocked by a Fortress Crab, when combat damage is assigned and dealt, the controller of the Boar will not be able to deal any combat damage to the defending player. When combat damage is assigned, the Boar’s controller must assign all five points of damage to the blocking Crab. When this damage is dealt, it will become a total of 10 points of damage, but all of it will be dealt to the Crab. It does not matter that this is more than necessary to be lethal damage to the crab–trample damage is assigned when combat damage is assigned. In this instance, none of the damage from the attacking creature could be assigned to the defending player, so none will be dealt to that player.