I've always found Reuniclus better than Alakazam. It's slower than just about all of OU but it has a stupid amount of bulk and a great SpA stat, and it keeps Magic Guard with which it can abuse Life Orb as it doesn't need a Sash. Here's the set:
Reuniclus @ Life Orb
Trait: Magic Guard
Bold Nature (+Def, -Atk)
EVs: 252 HP / 252 Def / 4 SpD
- Focus Blast
- Calm Mind
Quotes from opponents who have faced this on Showdown:
"Yeah, I have nothing for this Reuniclus"
"This Reuniclus is gonna sweep me"
"Why is Leech Seed not doing anything?"
"Well, I feel stupid. I thought I was Toxic stalling...."
1. Set up Calm Minds.
2. Recover when necessary.
4. Get KOs.
It does not die easily. Crithax is usually the reason for me. And they can't stall it out either. AND you get free LO boosts. I 6-0 people with this set. It's kinda scary how few people prepare for this, everyone expects a TR sweeper.
"Whether Castform the Weather Pokemon can weather the weather is dependent on whether the weather that it's weathering is the proper weather for it to weather. Whether the opponent can weather the weather is also subject to whether the weather that it's weathering is the right weather to weather. Whether Castform can weather the opponent is once again dictated by the weather and whether that weather is the favorable weather for weathering. But most importantly, you should know whether there will be weather to weather rather than what weather they will be weathering and whether they can weather that weather."
- Smogon's Castform analysis