Up ! Still no answer ?
Considering this debate, how would you understand the Action of Forest dragon ?
According to your vision of Toxic Hydra's Action :
1) You can play charge of the silver helm on him after triggering his Action
2) You have to consider "double" like bloodletters. 1 Action = double ; 2 Actions = triple.
=> You don't consider his present power when you trigger his Action, but until the end of the turn, you double (or triple...) the power he can gain or lose.
.. And nobody never played him this way, right ?
Forgive me for my mistakes, english isn't my native language.
You double the power each time you trigger it's action.
6-12-24 etc.