Necrozma by Drak-Arts on DeviantArt
Necrozma@Lum Berry
Ability: Prism Armor
252 Atk / 240 Spe / 16 HP
Adamant Nature
-Dragon Dance
-Photon Geyser
-Earthquake
-X-Scissor
Not the most innovative set I know, RU players will be pretty familiar with it, but i'm reusing it here since it actually lures Slowking fairly well. The sets pretty simple actually, Slowking comes in expecting the Meteor Beam set with the knowledge that with Colbur berry they can tank out and Scald the physical set's Knock Off. Instead Necrozma DD's on the switch and goes for X-Scissor or another DD the turn after, depending on how much HP the Slowking has remaining. X-Scissor is generallty worse than Knock Off but gets around Colbur Berry and also lets Necrozma slaughter Zarude and Obstagoon, which would otherwise wall the set. The EVs are to maximize damage and outspeed Noivern at +1, as well as Max Speed Neutral Nidoqueen and Toxtricity at +0. Alternatively if you feel like risking burn you could replace Lum Berry with Life Orb or Expert Belt, which lets you OHKO Obstagoon at +1 93% or 44% of the time respectively, and have a 50% and 6.3% chance to OHKO PhysDef Slowking at +2 respectively. However, I prefer simply chipping Slowking with something else and gaining multiple DD with Lum Berry, which is a greater power boost anyway.
Calcs:
+1 252+ Atk Necrozma X-Scissor vs. 252 HP / 252+ Def Slowking: 210-248 (53.2 - 62.9%) -- guaranteed 2HKO
+2 252+ Atk Necrozma X-Scissor vs. 252 HP / 252+ Def Slowking: 278-328 (70.5 - 83.2%) -- guaranteed 2HKO
0 SpA Slowking Scald vs. 16 HP / 0 SpD Necrozma: 96-114 (28.3 - 33.6%) -- 0.2% chance to 3HKO
252 Atk Guts Obstagoon Knock Off (97.5 BP) vs. 16 HP / 0 Def Prism Armor Necrozma: 276-325 (81.4 - 95.8%) -- guaranteed 2HKO
252 Atk Guts Obstagoon Knock Off vs. 16 HP / 0 Def Prism Armor Necrozma: 184-217 (54.2 - 64%) -- guaranteed 2HKO (no item)
+1 252+ Atk Necrozma X-Scissor vs. 0 HP / 0 Def Obstagoon: 248-294 (75.8 - 89.9%) -- guaranteed 2HKO after burn damage
+2 252+ Atk Necrozma X-Scissor vs. 0 HP / 0 Def Obstagoon: 332-392 (101.5 - 119.8%) -- guaranteed OHKO
+2 252+ Atk Life Orb Necrozma X-Scissor vs. 252 HP / 252+ Def Slowking: 361-426 (91.6 - 108.1%) -- 50% chance to OHKO