The Scorpion God
 
If I'm honest, I don't often play with -1/-1 counter cards in more open formats, only because I often end up playing with +1/+1 counter cards and I don't like the tracking and memory issues. It's somewhat easier since they made it that they "cancel out" if you have both on the same creature, but when you have some creatures in play with one and some with the other, you need to be very careful what color of dice or counters you're putting on whom. I might have to reconsider that, though, because the Scorpion God is a very strong way to knock out hordes of smaller creatures and even deal with indestructible gods from both Amonkhet and Theros (and red and black sometimes have trouble with the latter). Returning to your hand from the graveyard is very hard to deal with in constructed, but something I missed until someone specifically pointed it out is that if he's your commander, it lets him avoid the "tax" on the number of times he's been cast previously.
 
Constructed: 4/5
Casual: 4/5
Limited: 5/5
Multiplayer: 4/5
EDH/Commander: 4/5

The Scorpion God is certainly scary, even if it’s atypical for a God. It has no requirements for it to be able to attack or block (unlike the Theros-block or Amonkhet gods), but the body is maybe a bit smaller than the others? Make no mistake, a 6/5 for 5 is about what you’d expect from its cost, but it definitely pales in comparison to the efficiency of a Rhonas or a Heliod.
 
It has a potent effect that synergizes very well with all of the -1/-1 counter support in the block, and drawing cards is always good. Being able to stick more -1/-1 counters down for 3 mana makes The Scorpion God a good, reliable source of weakening, and it makes sense that it gets an ability that allows it to kill the Gods themselves. It’s hard enough to block, but it gets even harder to block when your board gets weakened.
 
Of course, killing it conventionally is but a temporary salve. It has a triggered ability that beings it back to the hand to be recast on your next turn if it dies. Exile is the only way to still it. It does a lot of damage and keeps coming back...I think it may be a bit slow for Constructed, but it's certainly a powerful card in its own right.
 
Constructed: 3
Casual: 5
Limited: 5
Multiplayer: 3.25
Commander: 4