Originally Posted by Fat Gazooki
Mandibuzz (again, that one specific one)
Here's a version-specific one, and one that you poor saps with White 2 are missing out on. I may be biased since Mandibuzz is one of my favourite Pokemon of all time, but I was willing to bend time for this chick and things worked out perfectly.
Mandibuzz has some seriously amazing bulk, it was taking super-effective hits and not even being 2HKO'd! Initially I used it as a Fly slave but when it got Nasty Plot, Dark Pulse and Air Slash I couldn't turn that down, especially not with the bulk to get off at least one guaranteed, if not two. Even though the special side is Mandibuzz's weaker attack-wise, after a couple of boosts not a lot can stop it.
Matchups against Gyms aren't usually kind, Elesa outright wins, Clay's stuff all has Rock Slide, there's no way Mandibuzz can beat Skarm one-on-one, Drayden is generally evil and Marlon I suppose is neutral. At least you can take down 3 of the Elite 4 with relative ease (and a bit of help from Weak Armor in my case).
Weak Armor may seem like the worst ability for it considering the defensive role it plays but it actually really helped. Sacrificing a bit of defense for Speed, especially after its special attack has been powered up, helped me power through both Marshal and Shauntal (I got lucky with the latter due to Drifblim deciding to use Acrobatics over any of its other moves...).
Leaning towards Top Tier here, walls don't usually do too well in-game but this one sure as hell does. Just make sure you're around Route 4 on Thursday or willing to change the clock.
Definitely disagreeing with Top Tier for Mandibuzz. As you said yourself, it matches up terribly with most of the gym leaders it's available for, which is one of the most important things to be able to do for a top tier Pokemon. Plus, it gets Air Slash and Dark Pulse at 41 and 46 respectively, meaning it spends 16 levels being very meh and not very useful only to have waste turns to set up in order to use its terrible Sp. Attack . Mine has missed kills often at +4 and sometimes even at +6. I'd say Mid Tier
at the most since it's pretty bulky and can afford to take a few turns to set up, but it does too little damage and is not very useful for most of the game for it to be Top.