Cement Shoes (unable to move under water XD )
Goodra@Leftovers/Damp Rock
Hydration
Sassy 252 HP / 126 SpA / 126 SpD
~ Rain Dance
~ Infestation/Protect/Rest/Dragon Pulse/Dragon Breath
~ Thunder
~ Muddy Water/Aqua Tail
The EVs could use some retooling but I think this is a very good mix of tankiness and utility. I was not impressed with the Assault Vest build, where the damage difference is far better compensated with Leftovers making you overall far bulkier and letting you use certain support or boosting moves because despite coverage power was always wanting. Rain Dance provides three benefits A) it removes status affects B) makes Thunder 100% accurate and C) powers up your water move of choice. Remember, 30% = 100% in pokemon so paralysis from Thunder is a semi-reliable occurance, allowing you to now outspeed pretty much everything now and potentially nab free turns of Leftovers healing. A stronger Muddy Water also has good potential in lowering the opponent's accuracy on top of this, making you extremely hard to hit, and unless you've been boosting, not likely to do much on top of this. Aqua Tail on the other hand gives you some mixed potential in case they send in similarly specially defensive behemoths. You have lots of options for your last move. Infestation traps and gets you the most out of your paralysis and accuracy manipulation, Rest for the immediate mega healing in case of emergencies, Dragon Pulse for more reliable STAB which, when combined with Water and Dragon I believe is unresisted outside of Whimsicott and Ferrothorn (who you will outstall, but Leech Seed is still annoying), or Dragon Breath for less power but additional opportunities of getting that valuable paralysis in.
If Slimer were a Porcupine
Goodra@Rocky Helmet
Gooey
Bold/Calm/Impish/Careful/Sassy 252 HP / 252 Df / 4 SpD
~ Rest
~ Sleep Talk
~ Infestation/Swagger/Outrage/Captivate/Toxic/Flamethrower/Sludge Bomb/Dragon Tail
~ Infestation/Swagger/Outrage/Captivate/Toxic/Flamethrower/Sludge Bomb/Dragon Tail
Goodra's natural special bulk is to the point where physical attacks and status become necessary, and this set handles both. Physical attackers risk Rocky Helmet damage on top of a speed drop, and Resttalk handles status as well as keeping you overall very healthy. Your last two options are far too numerous. Sludge Bomb is a decent attack that has a fair chance of Poison which makes it a huge battle of attrition for your opponent, or you could outright Toxic. Combined with Flamethrower you can handle steels barring Heatran, or you could simply use a Dragon move instead. With hazards Dragon Tail becomes very annoying where with Sleep Talk and Gooey you can go first far more often and phaze them through hazards. Brutal with Toxic Spikes. Captivate and Infestation relegate mixed walls to hitting you physically but relying on Infestation damage alone isn't a great idea. Swagger is a double edged sword, encouraging the attacks on the physical side which put you at bigger risk against certain things, or just makes it a hair pulling nightmare for your opponent.
Salty Sailor
Goodra@Leftovers
Sap Sipper
Sassy 252 HP / 4 Df / 252 SpD
Sassy 252 HP / 252 Df / 4 SpD
~ Substitute
~ Curse
~ Body Slam
~ Dragon Tail/Outrage
A single Curse puts you at Garchomp level attack and defense while maintaining your special bulk and having far better defensive typing. Substitute protects you from status and after a Curse or two can actually be hard to break. Body Slam is a reliable move with that oh so valuable paralysis chance that will allow you to maintain a speed advantage against many things even after Cursing. ****! Dragon Tail allows for powerful parashuffling, making it hard for the enemy to boost or reliably break your sub while Leftovers replenishes health. Or you could simply ****ing Outrage.
There, a great set for each of his abilities.