Glad I picked up a Marill in Pokemon Platinum. This game doesn't have a lot of water types. You can get Buizel early with great speed and attack, but the moves aren't that great. Azumarill is kind of underappreciated but it looks like it's pretty much as good as it was in the last games. So it's secretly a beast.
It's stats don't look impressive at first. It's got what look like mid-level tank stats, with high defenses but rather lacking attack stats and boosted HP. They usually come with the ability thick fat which will give a 50% defense boost against ice and fire, two types it already has natural resistance to. Useful if you want to... torment AI's who have fire or much rarer ice type moves, I guess. It just isn't that useful.
But if you look around for a bit, you can catch one with the rarer huge power ability, which renders the attack stat double of what is shown. So now, Azumarill's kinda sad base 50 attack stat is actually 100. To put that into perspective, a friggin Moltres has the same physical attack stat in this game. It's legendary-level.
So, with that ability, it is massively powerful as a physical attacker, with solid phys/spec defense and chonkin HP. It also knows the move rollout when you catch it as a Marill. Basically, it's a physical rock-type attack that binds your pokemon to only use that attack for up to 5 turns (or until it misses,) with the power doubling after each hit. You can't do anything until the cycle is broken. The first hit is 30, the next is 60, then 120, then 240, and then finally 480. Even 120 base damage is very high. I don't know if many other moves cross that in base damage, most moves that powerful have poor accuracy and you only get 5 goes with them total. Rollout gets 20 goes at landing streaks of 5 rolls. You have an absurd amount of damage tucked away in that move. It will do almost 1000 base damage across 5 turns. That's stupid high when a standard attack does 60-80 per one-turn use.
I can additionally go back and have it remember defense curl, a level 2 move that it would normally have forgotten by the time you catch it at level 20. That move usually only increases defense by a stage, but when used before rollout, it DOUBLES the base damage. So you start at 60. The 5th roll hits for 960 damage. Almost ONE THOUSAND base damage on a single turn in a game where an attack over ONE HUNDRED is already high! I mean, the 3rd one already hits for 240 at that point, which is dropping most really strong pokemon in the main game when you add in the legendary attack stat on the other end of the equation.
You can also slap-on a zoom lens to deal with the 90% accuracy, keep it from missing in the middle of sequence. Or you can play it slightly riskier and use a razor claw to instead up the critical hit chance for the odd mega roll.
I'm using this to roll through trainers with big teams. Literally rolling through them. I kinda don't worry much about what comes out next. By stage 2 or 3, typing and stuff kinda starts to matter a lot less. Rock doesn't have a type that it has zero effect on. And even halved by a resistance, it's still endgame level base damage and well beyond by the next hit. Nothing is surviving the next turn, when it hits for double that. Azumarill is a tank that can take a hit or two, so it will stay in the fight to land that. You could also consider that the huge power's base doubling offsets the resistances half-reduction. Add defense curl boosting and we are back at full huge power levels.
The downside is that Azumarill is kinda gimped as a water type by these stats. The most common strong water moves are special, not physical. The HM move Surf is a killer water attack that hits everything not levitating for a high base of 95 water damage, but it does rely on Azumarills weaker special. He learns a base 90 physical water move at level 47. Too bad, as you get the ability to teach surf no matter what, just as part of progressing. It's one the best water moves ever. Surf will still be great here, just not amazing. In the meantime, I have to think about how I want to pad out the typing. Get a fighting or ground move in there. Maybe even ice. It comes down to what I can get as a physical move.
This is what I like about these games. There are a whole lot of different ways to kick ass in different situations. Every pokemon has different, specialized strengths and weaknesses that all come together in your choice of ways. This is just one of many many ways to go.
Hell, this strategy sounds OP, but there's plenty in the game to break a rollout loop. Some pokemon have moves that break it by blocking all incoming attacks for a turn, with moves like detect or protect. They could throw a substitution that eats all of the damage before breaking. They could use minimize or double team to up evasion, or use one of the many accuracy dropping moves, either of which can make rollout pretty much unusable. They could use an attack move that induces flinching. A move like roar forces your opponent to switch pokemon. There's always fly and dig, too.
This is what I mean though. I know the game can beat me on this, it just won't try. :/