Oh my, that hydra looks like the perfect cuve topper for my soon-to-be UG deck! It's also sick with Exava, since it'd be a hasty, trampling 8/8 out of nowhere.
The Resonator sound awesome as well. Perhaps it'll end up like Sundial of the Infinite, but I think it has the potential to be so much more, mostly since ETB abilities have gotten stronger over the years.
I'm still waiting for my Scavenging Oozes, which will be great additions to the UG deck (Shambleshark's kind of not that good for an aggro deck, sadly), and I guess I'll be retiring my BUG flash/control deck for now... maybe I'll try out one of those Nivix Cyclops decks, but I'll have to make it RUG since I don't have any Boros Charms or the lands to support it. I think the RUG version is quite inferior to the WRU one, since Boros Charm's double strike is way better than Simic Charm's +3/+3, and its other modes are very relevant as well. I'll try the deck out and see whether it's worth running, or if I should just go straight to running the UG aggro deck.