Until the end of your next turn, you may play those cards
All told this is a mediocre card quality spell and a good card advantage card resulting in a very good card overall
Specifically, five toughness is only outmatched by eight creatures, four of which are mythic, and five others trade with it
The player will always target someone vulnerable to attack who hasn't assembled a defense yet, or who can block all five damage with something like a Fog Bank, and then get the cascade triggers to fall their way
The modes are quite different from each other, too, but giving your whole team hexproof, while maybe slightly over the top as most spells only target a single creature, is a good bit better than just giving hexproof to one of them
Kotis, the Fangkeeper Kotis, the Fangkeeper is one of these commanders that doesn't particularly support a horde of zombies, and is a fantastic theft commander that happens to be a zombie