This is an obvious exploit, just faced a deck built with it.
When combining floodwaters with tightening coils, your “attack” flips around to what I believe is the negative boundary (ie. negative infinite), but you still attack your opponent. When you do, you end up doing a mass amount of “negative” damage which in turn heals them for that amount.
Once that has happened, you cannot complete the match in any foreseeable period of time, because your opponent now has the maximum amount of HP that can be internally stored in that variable. Basically, they have infinite health now. The display still shows them at full health (eg. Kiora at 105) but no matter how much damage you do from that point forward, their health does not diminish.
I thought it was strange to see Tightening Coils in a drake haven deck, since it does not cycle, so it is obviously there to combo with floodwaters for this exploit.
Ironic part was that when I saw Drake Haven I started laughing. Joke’s on me though.
Above battle log shows: When floodwaters was cast, since Baral had already been hit with Tightening Coils, his attack value flipped around. He then attacked and hit the opponent which increased the opponent’s health.
Above image shows: How can opponent still have full health when I’m swinging for 150+ per turn?
//Edited Title and Censored Screenshot -Brigby