Torrent
No seriously, Shell Armor is barely anything for poor Samurott. It prevents critical hits to happen; yet Torrent magnifies Hydro Pump (and other Water-type attacks)' power for a lot.
A set I'd recommend:
Samurott @ Petaya Berry / Salac Berry
Trait: Torrent / Shell Armor
EVs: 252 SAtk / 252 Spe / 4 Atk
Naive Nature
- Substitute
- Hydro Pump
- Megahorn / Aqua Jet
- Ice Beam
The last Substitute should always trigger Torrent and the berry whatsoever. At 25% of health, the berry is eaten and a stat rises. Moreover, Torrent adds to Hydro Pump's power quite a nice punch. Shell Armor on the other hand prevents nasty crits while setting Sub up, but Torren't extra power is more favorable most of the time.
Samurott @ Life Orb
Ability: Torrent
EVs: 4 Def / 252 SpA / 252 Spe
Modest Nature
- Hydro Pump
- Ice Beam
- Grass Knot / Taunt
- Aqua Jet / Knock Off / Superpower
That's another viable set as an all-out attacker. Finally, physical Samurott is acceptable with Swords Dance, and Shell Armor can come in handy too, as it will prevent crits to break while setting up.
Samurott @ Lum Berry
Ability: Torrent
EVs: 120 HP / 252 Atk / 136 Spe
Adamant Nature
- Swords Dance
- Waterfall
- Aqua Jet
- Megahorn
The EV spread allows Samurott to outspeed neutral-natured base 55 Speed Pokemon such as Exeggutor and Golurk while granting as much power as possible with the rest to HP for some bulk.
When Johto starters will have HA, Physical Samurott will be outclassed by Feraligatr.
So Special Samurott is better imo.
