>>50850360And while on the subject, to the guy from last thread who'd asked me about Comp Hatt (sorry I didn't see the post until it'd been archived), there is indeed a reasoning behind why some people have started putting Speed EVs into their Hatterenes:
Toxapex.
It's literally just Toxapex.
With a very minimal speed EV investment, Hatterene is capable of hitting a speed of 107, which is just high enough to outstrip Toxapex's uninvested speed of 106. This allows Hatterene to generally destroy it much harder than it already does, and in the case of CM Hatts specifically, you can shred the thing before it's able to get off Haze. In fact, Toxapex becomes such dead weight in these instances that I've actually had opponents who make suicidal plays with their Toxapex or choose to sack it entirely in a desperate attempt to Haze or stall for time, which allows all the things Toxapex usually walls to run freely. And those don't include all the people who just forfeit when they see the thing die. It's pretty satisfying, and it also makes CM Hatt a lot more successful since Pex no longer threatens her with buff removal. As a lover of CM Hatt, this is actually what I use myself, so I speak from experience here.
At least, in OU and NDOU. I don't use speed invested Hatterene outside of the smogon metas, and I don't usually see other people with speedy Hatts outside of them either, especially not in BSS or VGC. I'd have to ask what format you were playing, since you claim to be using Magearna (which is banned in all four of those, unless you're doing the AG version of BSS that lets you fight people with six Zacians).
Funnily enough, prior to Magearna getting banned in NDOU, I found my Hatterene to actually be a pretty good check to all of her most common sets purely by just spamming Mystical Fire until they swapped or died. Even the WP/Shift Gear versions died to this. People very rarely used a steel move on Mag, so she won many games against them during the suspect. 
