Ok... a few friends and I have been having a debate on how and why Barrel Behind the Door acts the way it does... I finally have an explanation that fits ALL of the rules
A. Damage effect 1 causes 1000 (could be tremendous fire, this is an example)
B. Barrel Behind the Door is activated because legally the last thing to happen is Damage Effect 1 and that is a requirement
C. Healing Effect 1 (counter-trap) is activated healing 1000 by the activator of Damage Effect 1 (legal)
How would this resolve?
Here's my Final Answer
C. Healing Effect 1 resolves... player gains 1000 LP
B. Barrel Behind the Door resolves, and affects is Legal Target (Damage Effect 1 in this case)
A. Damage Effect 1 resolves and the damage is switched to the caster
Note, this should be Legal... ALSO the following explanations have been Derived from the rulings and the wording on the card
AA. BBtD cannot be chained to BBtD... this is because BBtD DOES NOT DEAL DAMAGE... It switches the TARGET of the effect of the Target of BBtD... BBtD DOES NOT DO DAMAGE... furthermore, when the damage effect resolves (target is switched) another BBtD CANNOT be activated because new cards cannot be added mid-resolution
BB. BBtD cannot be chained to effects that will not guarantee damage... This is where I got stuck... say, Dice Jar VS. BBtD... but I solved it... BBtD SPECIFICALLY SAYS... SWITCH damage you recieve to your OPPONENT... the possibility of SWITCHING damage your opponent recieves to yourself would be a violation of BBtD effect... and since you cannot Verify IF damage will be done to YOU (Keyword being YOU, not damage) the card cannot be activated (Dice Jar will always do damage to a player, damage IS guaranteed... however the target is not)
CC. Variable Damage cards... Ceasefire Vs. BBtD.... As long as damage is Guaranteed (at least 500 in this case) BBtD can be activated... BBtD SWITCHES the TARGET of the DAMAGE only... Therfor the VALUE of that damage is irrelevent
DD. 0 Damage potential... simple.... Exiled Force cannot be activated if it is the only monster on the field.... BBtD cannot be activated if it would Switch the target of 0 Damage.... since the game considered 0 Damage to be "Null Effect" (like in the case of Exiled force being the only monster
EE. Multitarget Switching... BBtD Vs. Tremendous Fire.... switch the damage you recieve to your opponent... This does work because "An effect that causes damage" Irrelevent of player select was activated... THIS IS THE SOLE requirement of BBtD... therfore the other player would recieve full damage for the card
FF. Player causes damage to themselves... there are probably no cards that do this, but... if your opponent WOULD do damage ONLY to themselves then BBtD cannot be activated since the effect of switching to your opponent can never be resolved (you cannot activate under the 0 Damage Potential clause)
And all that other stuff about continuous cards and trigger effects and what not
I found a way to resolve trigger effects: This is what we do... we each take a deck of normals cards and whenever a trigger effect is activated (say Cannon Soldier) we play a card "10 of Diamonds" or something to Represent the Cannon Soldier effect... this Card CAN be chained to by anything that can chain to the Cards effect.... by this reasoning, Continuous and Cost effects can not be chained to by certain cards because they are always active and thus never have a "10 of Diamonds" to respond to.... thats just how we do it... most players can just remember effects accordingly
by this reasoning
GG. BBtD cannot be chained to "Wave Motion Cannons" effect BECAUSE... WMC was played (X) turns ago... then it DID NOT DO DAMAGE so could not be chained... NOW it is activated by sending it to the graveyard due to its effect... Since a "10 of Diamonds" was not played, BBtD cannot chain to the damage
Let me know if my Barrel Behind the Door research is correct... cuz I would hate to have written all this just to find out I was wrong somewhere... but I'm mostly right as far as I can tell
PS: Ignore my "10 of Diamonds" thing, its just a PHYSICAL representation of an Imaginary effect
A. Damage effect 1 causes 1000 (could be tremendous fire, this is an example)
B. Barrel Behind the Door is activated because legally the last thing to happen is Damage Effect 1 and that is a requirement
C. Healing Effect 1 (counter-trap) is activated healing 1000 by the activator of Damage Effect 1 (legal)
How would this resolve?
Here's my Final Answer
C. Healing Effect 1 resolves... player gains 1000 LP
B. Barrel Behind the Door resolves, and affects is Legal Target (Damage Effect 1 in this case)
A. Damage Effect 1 resolves and the damage is switched to the caster
Note, this should be Legal... ALSO the following explanations have been Derived from the rulings and the wording on the card
AA. BBtD cannot be chained to BBtD... this is because BBtD DOES NOT DEAL DAMAGE... It switches the TARGET of the effect of the Target of BBtD... BBtD DOES NOT DO DAMAGE... furthermore, when the damage effect resolves (target is switched) another BBtD CANNOT be activated because new cards cannot be added mid-resolution
BB. BBtD cannot be chained to effects that will not guarantee damage... This is where I got stuck... say, Dice Jar VS. BBtD... but I solved it... BBtD SPECIFICALLY SAYS... SWITCH damage you recieve to your OPPONENT... the possibility of SWITCHING damage your opponent recieves to yourself would be a violation of BBtD effect... and since you cannot Verify IF damage will be done to YOU (Keyword being YOU, not damage) the card cannot be activated (Dice Jar will always do damage to a player, damage IS guaranteed... however the target is not)
CC. Variable Damage cards... Ceasefire Vs. BBtD.... As long as damage is Guaranteed (at least 500 in this case) BBtD can be activated... BBtD SWITCHES the TARGET of the DAMAGE only... Therfor the VALUE of that damage is irrelevent
DD. 0 Damage potential... simple.... Exiled Force cannot be activated if it is the only monster on the field.... BBtD cannot be activated if it would Switch the target of 0 Damage.... since the game considered 0 Damage to be "Null Effect" (like in the case of Exiled force being the only monster
EE. Multitarget Switching... BBtD Vs. Tremendous Fire.... switch the damage you recieve to your opponent... This does work because "An effect that causes damage" Irrelevent of player select was activated... THIS IS THE SOLE requirement of BBtD... therfore the other player would recieve full damage for the card
FF. Player causes damage to themselves... there are probably no cards that do this, but... if your opponent WOULD do damage ONLY to themselves then BBtD cannot be activated since the effect of switching to your opponent can never be resolved (you cannot activate under the 0 Damage Potential clause)
And all that other stuff about continuous cards and trigger effects and what not
I found a way to resolve trigger effects: This is what we do... we each take a deck of normals cards and whenever a trigger effect is activated (say Cannon Soldier) we play a card "10 of Diamonds" or something to Represent the Cannon Soldier effect... this Card CAN be chained to by anything that can chain to the Cards effect.... by this reasoning, Continuous and Cost effects can not be chained to by certain cards because they are always active and thus never have a "10 of Diamonds" to respond to.... thats just how we do it... most players can just remember effects accordingly
by this reasoning
GG. BBtD cannot be chained to "Wave Motion Cannons" effect BECAUSE... WMC was played (X) turns ago... then it DID NOT DO DAMAGE so could not be chained... NOW it is activated by sending it to the graveyard due to its effect... Since a "10 of Diamonds" was not played, BBtD cannot chain to the damage
Let me know if my Barrel Behind the Door research is correct... cuz I would hate to have written all this just to find out I was wrong somewhere... but I'm mostly right as far as I can tell
PS: Ignore my "10 of Diamonds" thing, its just a PHYSICAL representation of an Imaginary effect