What Pokemon surprised in being either really good or really bad?

[Ti4558]

The Good: Sableye really surprised me in how good he was against physical attackers when I was battling online. He took down a garchomp and a few other strong Pokemon by just using confuse ray, will I wisp, foul play, and recover with the prankster ability.

The bad: I had a hard time using gengar while battling online but I guess I just wasn't using a very good attacking strategy.

[Serebii!]

I had the same with Gengar after getting a shiny Ghastly I really wanted to use it a lot but never got much success

[Blany]

During Random Matchup on Wi-Fi, Scizor greatly impressed me and I decided to get one. When I used one, IV Bred in Attack and Hp, which had Perfect IVs, along with the Adamant Nature and EV Training, I thought that it would single-handedly defeat or significantly damage the opponent's team. However, this did not happen... and it ended up having unsatisfactory Attack for some reason...

[SimH8]

Good: My Heracross always seems to do amazingly in the battle subway, usually manages to take out at least one enemy pokemon. Also does well against my friends.

Bad: I was very excited about using an EV trained Aggron with it's amazing defense, however it's 4x weaknesses to ground and fighting made it hard to use, so I replaced it with a Donphan.

[lavaburst14]

Good: My Milotic, Nico surprises me daily in OU, and even against UBERS(that's right! UBERS!) Milotic's bulk if used with a calm nature and 252 hp 252 sp.def, and 4 def EV set and with ice beam/scald/recover/toxic with a wacan/rindo berry can take down even a Thundurus-T if used correctly. For example, Milotic endures an electric attack from Thundurus one turn with wacan berry, uses ice beam, and then takes out Thundurus next turn with ice beam again. It really works! Even if paralyzed, physical defense rises due to it's ability Marvel Scale. Take that smogon tiers! xD

Bad: Landorus-T you sadden me. One icy wind in a VGC style match takes you down to less than half HP, ice beam takes you down, and even a bulky varient in VGC match while two ice beams are aimed at him he's toast! Sorry Landorus fans...

[DarkSword39]

Good: Torkoal. It has enough defense to take a bunch of hits, and its special attack is good when you have modest nature. Overheat and on a Trick Room team, oh boy, Torkoal is very good.

Bad: Gyarados. Maybe I got a very (and I mean very) frail Gyarados, because after a thunderbolt it was gone. And for attacking, it wasn't anything special.

[Papousse]

I was surprised of the strength of my Luvdisc, back in my Sapphire game. It managed to defeat a Gyarados only with Attract, Ice Beam and Surf and was very useful at the Elite 4, especially when I came to Steven Stone.

[TanBun]

good: Seel. Good defense, good moveset (Rest, Ice beam, Surf,Rain dance) Seel is reaally reall annoying

bad: Beedrill. Awfu ldefense, bad moveset etc. Don't have to explain

[your boss]

Good: Gyarados, I'm was pleased how awesome it's SubDD set is in the Rain, being able to set up on -2 sp attack Latias and others related.

Bad: Liepard, I thought this would be a prominent member on my team but instead it ends up being KO'd by about everything. At least it had Prankster to make up for it.

[Azimuth1011]

Good: I have always perceived Starmie to be incompetent, but it won several unexpected victories in WiFi battling. Now that is totally unexpected.

Bad: Lucario disappointed me. I thought it would be a good Pokémon for priority moves but it always ends up in the dumps by just a Flygon.

[Zoruaruler]

Good: Torkoal. It has enough defense to take a bunch of hits, and its special attack is good when you have modest nature. Overheat and on a Trick Room team, oh boy, Torkoal is very good.

Bad: Gyarados. Maybe I got a very (and I mean very) frail Gyarados, because after a thunderbolt it was gone. And for attacking, it wasn't anything special.

Uhm..Gyarados is Water/Flying. Which means he's even more weak to electric type attacks than a normal water or flying type. And with a move as good as thunderbolt, of course he's going to be taken down in one shot.

And at the guy above me, Lucario is taken down by Flygon because Flygon is a flying type and that has an advantage over the fighting type Lucario.

You guys can't just expect to send in a Pokemon and have it destroy the other team. If it does, it means the other team was either unbalanced, the trainer didn't have very good leveling/stats, or the trainer was having an off day and their strategies weren't working how they wanted them to.

[Mystical Jackal]

Good: Ludicolo surprised me because of its typing, movepool and ability. Despite the stats aren't that high, it helped me a lot in Emerald Frontier.

Bad: Gallade in Platinum. Although he was with a nice moveset, for any reason it sucked. I think it was presumably low IV's.

[I-am-the-peel]

Good: Skarmory on a rain team amazes me. I know it'd be great with the lowered weakness to fire, but despite the 100% accurate thunder, and no boosted special defense in a sandstorm, Skarmory works well in setting up spikes and stealth rock, and roosting away it's health. Really good pokemon for me to use imo.

Bad: Haxorus to me, was incredibly frail. I used a dragon dance+outrage set with adamant nature and full investment in attack and speed, and it was easily outsped by the likes of Salamence and Landorus, which were enough to quickly take it out. I believe it will need more support, say a passed substitute or screen support, to better get it's sweep ready, though I'm still doubtful on it.

[FallBird]

Good: Stunfisk, and some other unloved fifth gen pokemon. Did a runthrough where I caught every pokemon I encountered (no same species catches though) on black and raised them all to 55 through rotating who was on the team, to get to know the new pokemon better - some of them really surprised me with how well they did against the in game trainers! Stunfisk in particular stood out, because I thought he was going to be a real struggle to raise. Turns out he was zapping trainers left and right and actually wound up being an asset!

Bad: Cofagrigus. I hate my Cofagrigus. He's from the same run as the aforementioned Stunfisk, and I really expected him to be awesome. Instead, I found him fainting all the time as a Yamask, having weak attacks, even the STABs, and being overall awful, even against pokemon that he should have had a type advantage over! I thought it would get better when he evolved to Cofagrigus, but needless to say, he was still just as awful, but with better defense. Cofagrigus and Liepard are the only two pokemon I didn't stick with on that run, and are currently shoved in the back of the box because they were just awful. It was kinda funny, because I really expected Cofagrigus to be amazing!

And at the guy above me, Lucario is taken down by Flygon because Flygon is a flying type and that has an advantage over the fighting type Lucario.

Flygon.. is definitely not a flying type...

[TheDarkKnightFalls]

Good: Volcarona. I thought it was fragile and oh-ok-I-won't-use-it, but it was amazing as a sweeper. Even in rain it is really good.

Bad: Gengar. Its awful defenses would just let it get KO'ed by the foe's Excadrill.

[emboarrocks]

Good: Gyrados. Switch in on jellicent or something and set up sub. Then DD a few times and GG.
Bad: Kyurem-B. No physical movepool, bad speed, outclassed by most other dragons. Never thought I would say this about a 700BST legendary but... yeah.

[Missingno.Fan]

I remember Onix surprising me when I was younger. I thought it was going to be really strong, but it to be an epic fail.

[SapphireL]

I've been using Durant in online battles. That thing is strong! She's also pretty fast. Hustle and Hone Claws is all it takes.

[Lucina Archaelis]

Good: Mandibuzz. I was trying to catch it to trade to the GTS for a Braviary, but I decided to use it first and... it has become one of my favorites. I mainly hated it for its design, but grew to love it and she can last well on a battle as she is kinda my powerhouse on my Black Team XP

Bad: Arbok.... I simply ADORE Arbok, but its attacks by level up were, to me, not so powerful and it was knocked out pretty bad most of the time in battles so I had to swith it out every... some battles <_> I had to switch it out of my team for another Pokemon >:

[telivisionhead]

Good: Vannilux, Alot of people dont like the Ice cream cone pokemon of Unova so I used it and it actually rocked! Taking down skyla's gym and beating up Iris.

Bad: Raticate..... I saw marriland doing a wedloche on pokemon heartgold and he had Carrot the raticate. I did my 2nd playthrough of pokemon soul silver and this was the first time I didnt just use my starter and legendaries, i trained other pokemon and I had a raaticate named Carrot though it was a girl unlike Marriland's raticate that was a boy.
My pokemon were underleveled so in the end I ditched raticate so I could fit Lugia on my team. Raticate was useless! I only used his attack crunch because I acidently deleted ferligaters crunch and raticates crunch was still HORRIBLE! Why did I use raticate?