SMITE

As Jormungandr, fully charge Consuming Bellow and kill 2 enemies with it.

I unlocked this by killing 1 god and 1 minion with a single use, so this appears to be glitched in a good way.

The above glitch now appears to have been patched, so you must get a double kill with Consuming Bellow.
This has also been made harder by a nerf to Consuming Bellow, that puts that ability on cooldown, even if you are stunned before being able to deal damage (so enemies with a stun can completely screw up your attack.) This has also now been adjusted, but you still need to be careful with enemies that have stuns or silences.

Consuming Bellow is Jorm's second ability. You have a short wind up and then you unleash a bellow that damages and trembles It is charged by being nearby to the Venomous Haze clouds created by your 1, your ult and your 3. You need 3 Venomous Haze clouds nearby to become fully stacked when you use Consuming Bellow, and then use it to kill two enemies in a single use.
What I find works best is to throw a Venomous Haze cloud towards an enemy and then using your 3 to stealth. Travel towards the cloud you threw earlier and then burst up from your stealth inside the cloud. This creates two more in whichever direction that you are facing. You can then use your Consuming Bellow on nearby enemies and try to get two kills.

Another method is to use your ult and in a small triangle shape around an enemy god, as each emerge produces a Venomous Haze cloud. Once your ult finishes, you can use the three clouds created by your ult to charge consuming bellow.

Building items that are a bit more in a bruiser style rather than all out defence works well here, as you'll have a good mix of damage and defence, which are both needed. My build when I got this was Shoes of the Magi, Void Stone, Genji's Guard, Soul Reaver and Mantle of Discord.

Max out your 2 first as well, as it does a decent amount of damage if you can hit it, even without charge from Venomous Haze pools

Definitely best attempted in Arena.

I managed to capture my unlock of this in a video;

I just got this achievement on Friday, (4/26/19.) Looks like you have to hit 2 Gods but only kill one.