I’m sure there are many questions as to why this occurs and there is no text in the GC that says that it deals bonus damage to the BM. I was quite sure people would have figured it out, but I guess not many have. If you know fighting games, you should be able to see why BM takes massive damage from the GC.
The key here is to see the interaction of the cannon ball when it hits the troops. Every single troop that gets hit by a GC’s cannon ball does one thing that the BM does not do, which is knocking back the troop.
What I think happens is, when a troop is knocked back, it is given an invincibility frame which prevents further damage from the cannon ball. An invincibility frame is something usually found in fighting games, where a hit will knock a target back and prevents it from getting combo-ed without a chance of retaliation.
The main use of invincibility frames in fighting games are dodge moves where you can voluntarily do an action/roll/attack that allows a timeframe (usually 0.5-1sec) which you cannot be hit. These moves are used strategically to dodge enemy attacks and allow for a combo-starter.
When a witch/barb/giant is hit by the giant cannon, it gets knocked back a little which prevents further damage from the moving cannon ball. These troops have a hit box (Wiki) and a harmed when the cannon ball touches them and causes them to be knocked back. But when the cannon ball travels through the BM, he is not knocked back and is hit every frame the cannon ball goes through him. This is what is causing the apparent 10x damage multiplier towards the BM.
You can see this by the BM losing health over a period of time instead of an instance. If it were a flat 10x multiplier, the BM would lose that health when the cannon ball touches him, not slowly (relatively) when the cannon ball passes through him. Another thing is that the angle of the cannon ball can vary the multiplier. Sometimes with the GC aiming while the BM is moving, it will “miss” and only deal 2-4x extra damage instead of the normal 10x because it passes through less of the BM’s hit box. All this evidence points towards the problem of BM not getting knocked back when the cannon ball is hitting him
In another game I used to play (something like a fighting game), the Warrior had a skill called “Iron skin” so when it is used, the Warrior will never be knocked back or his skill interrupted. The Sorceress had another skill called “Fire Wall” which hits around her and launches the enemy upwards. A normal person would be hit once, launched upwards and continue taking 3-4 more hits. A Warrior with iron skin on would take 30-40 hits losing most of their health in one attack. This is akin to what is happening to the BM.
The fix would be simple, allow the BM to be knocked back by the GC’s cannon ball. Otherwise the BM is in a really sad state right now and I’m more confident now in letting him sleep to lvl20 while I raid daily