The first ability is the one that Hydra decks care about, as it doubles any counters that its controller places on a permanent or player
Unlike Poisonous, Toxic directly modifies the type of damage being done, which means there is no triggered ability involving adding Poison counters to the player
Players can also look forward to some new and exciting trainer cards, including a new rule-bending Delta Species count Trainer, as well as a powerful new Fist of Night theme
If a card with harmonize is put into your graveyard during your turn, you can cast it if it's legal to do so before any other player can take any actions
With almost two-thirds of the deck cycling for a single mana(!), it becomes inevitable that you will draw multiple copies of this absurdly large Lightning Helix, and at this point, its hard to argue that it needs to do anything else to dominate
A all-in commander that can protect itself can be indispensable, giving your glass cannon some much needed resiliency