http://replay.pokemonshowdown.com/customgame-274518457 This seems to be a Mega Cup (or whatever it's called) battle.
(R) Mega Mawile gets cheeky, thinking it can set up a Swords Dance on Mega Lopunny. It gets 2HKOed.
(R) Mega Kangaskhan apparently lacks Fake Out, because Mega Lopunny one-shots it. I could see not running it if you don't need to Mega safely, but then why send it in?
(L) Mega Lopunny runs Focus Punch -- what, is HJK not cutting it?
(R) Fails to punish Mega Lopunny's arrogance -- Mega Lucario sets up a Nasty Plot and is one-shotted by Mega Lopunny.
(R) After setting up a Dragon Dance (Which I can see I guess, it can survive the HJK and KO back), Mega Charizard X uses... Earthquake. It does not OHKO Mega Lopunny, and Mega Lopunny KOs it in return.
(L) Uses High Jump Kick on Mega Latios, when we KNOW it's not choiced. This, incidentally, means that Mega Lopunny is Adamant.
(R) Mega Latios takes the opportunity to set up sneaky pebbles. So apparently this ISN'T a purely Mega Cup battle, though one then wonders what exactly is permissible in terms of normally-illegal moves.
(L) Switches Mega Lopunny out of Mega Pinsir, allowing the latter to set up a Swords Dance. It's not like Right has attempted to set up literally every time it didn't get KOed immediately or anything.
(L) Runs a Mega Rayquaza that is slower than Mega Pinsir.
(L) Sacs Mega Charizard Y and Mega Kangaskhan for no apparent reason. Not that either was likely to do a ton of work, but they could at least be switch fodder against Mega Latios.
(L) Runs a Mega Diancie that's slower than Mega Pinsir. It gets OHKOed.
(L) Runs a FUCKING MEGA SALAMENCE that's slower than Mega Pinsir. It gets OHKOed.
tl;dr Lots of thoroughly terrible plays on both sides, and Left makes some questionable-at-best teambuilding decisions.
EDIT: Here's another:
http://replay.pokemonshowdown.com/customgame-274527909 I won't question the 'mon choices, because for all I know there's some kind of condition on that, but:
(L) After putting Typhlosion to sleep, Darkrai decides to spam Dark Void until it wakes up. Once, maybe twice is excusable, but at a certain point you should figure out that the opponent isn't gonna switch.
(L) Doesn't bother attacking Typhlosion after it wakes up, instead going for Disable. It doesn't take.
(R) With a crit and two flinches (and, potentially, speed tie wins), Typhlosion gets extremely lucky and takes out Mega Charizard X with three Rock Slides.
(R) What, Sharpedo doesn't use Protect? Save for Espeed, that could actually check Mega Ray with like, Ice Beam or Ice Fang. It doesn't. Oh well.
(L) Body Slam Mega Mewtwo X. It manages to KO Greninja, but unsurprisingly, it's less effective against Gengar.
(R) Shadow Claw Gengar. Does decent damage to Mega Mewtwo X on a crit, but is otherwise exactly as weak as you'd expect.
(L) Mega Mewtwo X uses Drain Punch on Gengar with expected results, then switches out. Honestly it's hilarious to watch Gengar wall stuff.
(L) Air Balloon on KyuB.
(R) After Focus Blasting KyuB to within an inch of its life, Gengar goes for the Focus Blast again. I can maybe see wanting to catch Dialga on the switch, but given that KyuB is about to KO you with Fusion Bolt, a more reliable move would be advisable. Fortunately for Right, it pays off.
(L) Uses Earthquake on Gengar. I would almost write this off as a genius attempt to fish for Destiny Bond, but then it uses Draco Meteor the next turn anyways into
that Destiny Bond.
(L) Decides that Body Slam is the best move for Mega Mewtwo X to use on Mega Lucario, even though Drain Punch would OHKO and heal Mewtwo back up nicely, leaving it in a nice position to handle Electivire. Mega Lucario KOs it with Crunch.