Heart of Corruption

First, I would like to say thank you to the Dev's who (it would seem) lowered the HoC's health enough to make a splash on the April 1st attack.  I know I appreciated this as well as the community!  

Now for the information I have gathered from my recent attacks...  Sending 3k T2 Knights produced 1 corrupted square.  (3k knights at an attack of 61 each = 183,000 attack...I am not including any commander or prestige bonuses.)  A second attack of 3k landed as well as 2k more, and only two squares appeared.

Now, I also sent close to 10k T2 dark elves from the far north.  My city diplomacy info tells me that 5k dark elves have an attack of 155,000.  This lines up with the attack information above, since only 1 square appeared after they all landed.

I can verify that diplomatic units to add to the corruption.  This all seems to be happening on the amount of damage done to it.  Now, the total number of squares (once it is fully corrupt) is 73.  This means that the total plant needs to take around 14,600,000 attack damage.  WOW.

There must be something super special about the tentacles to merit all this.  If only we knew what that was so we could justify sending so many troops to their death....  *sigh*

It should be easy to calculate how many troops are needed.  (^_^)

Edit:  Also, I have ruled out small attacks in rapid succession as being a factor to speed this up.  The 10k T2 thieves I sent were all sent out in groups of 10 over the span of several hours...  this seems to have done nothing...  rather, the attack power is what it appears to be based on.  Could magical units speed this up?  Unknown at this time...