I'm gonna copy over a post I made on the Aerodactyl thread about how much I'm enjoying using Mega-Aerodactyl on my stall team atm:
So, stall has a rough time choosing a mega and some such teams even go without one. The defensive options are basically Mega-Venu, Mega-Scizor, Mega-Toise and Mega-Aggron, with most of the other megas being chosen occasionally to proven offensive presence but really not serving as stall Pokemon. Another thing stall has trouble with is BirdSpam (Mega-Pinsir backed up by Talonflame) and its cousin PinsirZone (using Magnezone to trap Skarm for Pinsir). Skarm is the most popular counter for Mega-Pinsir on stall, so PinsirZone in particular is a big issue. Additionally, stall players like myself can be dissatisfied with Skarm's lack of offensive presence and general predictability serving as a constraint on teambuilding.
Mega-Aero comes to the rescue as a pokemon that does very well against BirdSpam without being vulnerable to trapping from Magnezone, and also serves as a built-in source of offensive pressure against the scary HO teams by outspeeding most all of their non-scarfed mons and threatening them with powerful EdgeQuake attacks. Here's a set I'm currently testing:
Aerodactyl @ Aerodactylite
Ability: Pressure
EVs: 200 Atk / 88 Def / 220 Spe
Adamant Nature
- Roost
- Stone Edge / Rock Slide
- Ice Fang / Earthquake
- Aerial Ace / Taunt / Defog / Stealth Rock
220 Speed EVs outspeed +1 Adamant Dragonite after Mega-Evolving (which is just above Greninja) and outspeed max speed 110s (Latis and Gengar) before Mega-Evolving.
Mega-Aerodactyl is actually a counter (in the correct sense of the term) to Mega-Pinsir, and with a very small defense investment can counter Pinsir even with SR up:
252 Atk Aerilate Mega Pinsir Return vs. 0 HP / 88 Def Mega Aerodactyl: 128-151 (42.5 - 50.1%) -- 0.4% chance to 2HKO
252 Atk Aerilate Mega Pinsir Quick Attack vs. 0 HP / 88 Def Mega Aerodactyl: 51-60 (16.9 - 19.9%) -- guaranteed 6HKO
Return + Quick Attack does less than 75% (so you counter with SR up), and if you come in on an SD you're fine since you outspeed and OHKO with any rock move (even Smack Down). Mega-Aero also fares decently well against Talonflame, M-Pinsir's partner in crime:
252+ Atk Choice Band Talonflame Brave Bird vs. 0 HP / 88 Def Mega Aerodactyl: 122-144 (40.5 - 47.8%) -- guaranteed 3HKO
252+ Atk Choice Band Talonflame Flare Blitz vs. 0 HP / 88 Def Mega Aerodactyl: 122-144 (40.5 - 47.8%) -- guaranteed 3HKO
This is a counter if SR is down. If SR is up it can't switch into BB (because damn Gale Wings), but can switch into Flare Blitz as you outspeed and can either Roost off damage waiting for it to switch or kill itself from recoil, or just smack it with your rock STAB.
Aero doesn't really want to tank too many other attacks, but its bulk is reasonable so it can switch in on predicted resisted hits. When it does get in, it goes to town, especially against HO. The above set is massively threatening to pokemon like Landorus, non-scarf Keldeo, Latis with any prior damage, beats all Mega-Venu sets, etc. It isn't a wallbreaker by any means, but against a weakened offensive team it is not too difficult to clean up with. It can also dent most offensive pokemon pretty hard earlier in the game, and if they can't regenerate their health, that makes your job as a stall player much easier.
I think this is the best 4 moves to roll with. Roost and a Rock STAB are pretty much mandatory. The choice is yours between Stone Edge and Rock Slide. Rock Slide KOes the pokemon you absolutely need to KO (that's the birds) with a higher hit rate, but Stone Edge is noticeably stronger when you're hitting random other offensive pokemon. You can choose between Ice Fang and Earthquake for your next attack. Earthquake hits Mawile (but you lose to +2 Sucker Punch anyway), Heatran (but Stone Edge 2HKOs after SR), and Excadrill (but you lose if sand is up), while Ice Fang lets you OHKO Garchomp, counter Landorus, and beat Gliscor. You'll inevitably miss whichever one you don't pick, but I'm rolling with Ice Fang at the moment because it beats the threats that are more relevant for my team. The last slot is where the most choice comes in. Aerial Ace benefits from Tough Claws and so is fairly strong, giving you a way to OHKO Keldeo, Heracross, Medicham and Breloom. Given that these are all problem Pokemon for stall, having a sure-fire method of dealing with them is a fairly attractive option. However, there are others available to you, which I've listed in order of what I believe to be viable. Taunt turns Aero into a pseudo-stallbreaker, still dealing with the relevant threats, but now beating Chansey, Skarm (although Lefties + SE Misses makes this not something to rely on), Mew, defensive Mega-Venu, and other stall Pokemon. If you pick Taunt, you need Earthquake in the previous slot for EdgeQuake coverage. I think Taunt is a very real choice, however, there are better stallbreakers (for example, Aero isn't beating things like Quag, Gliscor, etc). Less viable is Defog, which is admittedly a very useful move. However, I think putting M-Aero as your defogger is stretching him quite thin as he isn't bulky enough to Defog often. Lastly is SR - while Aerodactyl is a decent suicide SR lead for HO with Taunt and Stealth Rock, I think there are much better things for him to be doing on stall, and you're almost certain to have a spot for it elsewhere in your lineup.
Overall I've been quite happy with Mega-Aerodactyl in my (admittedly limited) testing of him on stall. While he struggles to make a case for himself above other, more threatening Mega-Evolutions on offensive teams, stall doesn't have too many Megas to choose from and Mega-Aerodactyl fills a couple of very useful (and quite difficult to fill) roles. You guys should try him out if you get the chance.