Mantine as a
Hard Check/Counter
Mantine @ Leftovers
Ability: Water Absorb
EVs: 252 HP / 240 Def / 16 SpD
Calm Nature
- Scald
- Roost
- Defog
- Toxic
Pretty simple and straightforward. Since this Magearna set lacks Thunderbolt and Shift Gear is only Speed boosting functionally, it has no particular way to break standard Mantine barring the use of its Z-move, which still will not KO Mantine from full after SR. No other move it carries is capable of achieving a 2HKO after Stealth Rock, since Fleur Cannon will suffer the -2 and gimp follow up damage. Even if Magearna gets +1 off a KO, Mantine can survive a +1 Fleur Cannon after Stealth Rock on the "revenge" and Roost back up to stalling health, while Shadow Ball, the next strongest option, remains out of 3HKO after SR range even at +1 (barely 10% chance with Modest).
252 SpA Magearna Twinkle Tackle (195 BP) vs. 252 HP / 16+ SpD Mantine: 214-253 (57.2 - 67.6%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
252+ SpA Magearna Fleur Cannon vs. 252 HP / 16+ SpD Mantine: 157-186 (41.9 - 49.7%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
252 SpA Magearna Fleur Cannon vs. 252 HP / 16+ SpD Mantine: 144-169 (38.5 - 45.1%) -- 76.6% chance to 2HKO after Stealth Rock and Leftovers recovery
252 SpA Magearna Shadow Ball vs. 252 HP / 16+ SpD Mantine: 59-70 (15.7 - 18.7%) -- possible 6HKO after Stealth Rock and Leftovers recovery
+1 252 SpA Magearna Fleur Cannon vs. 252 HP / 16+ SpD Mantine: 213-252 (56.9 - 67.3%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
+1 252+ SpA Magearna Fleur Cannon vs. 252 HP / 16+ SpD Mantine: 235-277 (62.8 - 74%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
+1 252+ SpA Magearna Shadow Ball vs. 252 HP / 16+ SpD Mantine: 96-114 (25.6 - 30.4%) -- 10.9% chance to 3HKO after Stealth Rock and Leftovers recovery
+1 252 SpA Magearna Shadow Ball vs. 252 HP / 16+ SpD Mantine: 88-104 (23.5 - 27.8%) -- guaranteed 4HKO after Stealth Rock and Leftovers recovery
The one scenario where Magearna is completely sure to beat Mantine is at +1 using Twinkle Tackle.
+1 252+ SpA Magearna Twinkle Tackle (195 BP) vs. 252 HP / 16+ SpD Mantine: 352-415 (94.1 - 110.9%) -- guaranteed OHKO after Stealth Rock
I only debate Hard Check vs Counter since Mantine does have to be wary (if not necessarily afraid) of the Z-move, which is not just this Magearna's option but a fairly common one in general. That said, that is exactly one option this Magearna can use one time to try and break Mantine, and since it lacks recovery even Mantine's meager Scald is enough chip damage (especially with a Burn proc) to force Magearna out, it's not an option to fish for Fleur crits or anything. Mantine is a fairly reliable answer to non T-bolt sets for Balance or occasional Stall teams. It's important to keep Mantine healthy though since it lacks Toxapex's Haze to make things safe for the teammates and thus has to stay alive until the stop is no longer needed.