Feebas must have Oblivious ability to become a Competitive Milotic.
You can run many Milotic builds, based on his role in your team. If you want it to be Competitive, i can suggest you 2 builds:
Milotic @ Sitrus Berry
Ability: Competitive
Level: 50
EVs: 240 HP / 140 Def / 32 SpA / 96 SpD
Modest Nature
IVs: 30 SpD
- Hydro Pump
- Ice Beam
- Hidden Power [Electric]
- Protect
This one runs Hidden Power Electric to hit Azumarill, Suicune and Lapras (which would wall you otherwhise, except if you run Dragon Pulse but then Azumarill walls you anyway) and MegaCharY under the sun. Hydro Pump to maximize damage after the +2 boost, because we don't need Scald to burn anymore, we want to kill. Some damage calculations here:
252+ Atk Parental Bond Mega Kangaskhan Double-Edge vs. 240 HP / 140 Def Milotic: 168-199 (84 - 99.5%) -- guaranteed 2HKO
252+ SpA Mega Charizard Y Solar Beam vs. 240 HP / 96 SpD Milotic: 136-160 (68 - 80%) -- guaranteed 2HKO
252 SpA Life Orb Thundurus Thunderbolt vs. 240 HP / 96 SpD Milotic: 151-179 (75.5 - 89.5%) -- guaranteed 2HKO
252+ SpA Ludicolo Giga Drain vs. 240 HP / 96 SpD Milotic: 84-102 (42 - 51%) -- 2% chance to 2HKO
252+ Atk (M)Salamence Double-Edge vs. 240 HP / 140 Def Milotic: 84-99 (42 - 49.5%) -- guaranteed 3HKO
+2 32+ SpA Milotic Hidden Power Electric vs. 0 HP / 0 SpD Mega Charizard Y: 92-110 (60.1 - 71.8%) -- guaranteed 2HKO
+2 32+ SpA Milotic Ice Beam vs. 36 HP / 116+ SpD Thundurus: 146-174 (91.8 - 109.4%) -- 56.3% chance to OHKO
+2 32+ SpA Milotic Hydro Pump vs. 40 HP / 0 SpD Hitmontop: 130-154 (100 - 118.4%) -- guaranteed OHKO
+2 32+ SpA Milotic Hidden Power Electric vs. 0 HP / 0 SpD Gyarados: 204-244 (120 - 143.5%) -- guaranteed OHKO
This one can surprise your enemy:
Milotic @ Weakness Policy
Ability: Competitive
Level: 50
EVs: 240 HP / 4 Def / 32 SpA / 232 SpD
Modest Nature
IVs: 30 SpD
- Hydro Pump/Scald (because on an hypothetical +4 you always need to hit)
- Ice Beam
- Hidden Power [Electric]/Recover (if your team has Electric support)
- Protect
This set needs a bit of support in order to work better: Arcanine and MegaManectric are the best supports because of Intimidate (we don't have much physical defensive bulk) and SNARL to reduce opponent's SpA, cause you want to be hit by a supereffective move in order to reply with a +2 attack. A Special bulk is needed because of Electric and Grass moves are mostly special. If your enemy activates your Competitive and Weakness Policy boost then you have a +4 Milotic.
You can run many Milotic builds, based on his role in your team. If you want it to be Competitive, i can suggest you 2 builds:
Milotic @ Sitrus Berry
Ability: Competitive
Level: 50
EVs: 240 HP / 140 Def / 32 SpA / 96 SpD
Modest Nature
IVs: 30 SpD
- Hydro Pump
- Ice Beam
- Hidden Power [Electric]
- Protect
This one runs Hidden Power Electric to hit Azumarill, Suicune and Lapras (which would wall you otherwhise, except if you run Dragon Pulse but then Azumarill walls you anyway) and MegaCharY under the sun. Hydro Pump to maximize damage after the +2 boost, because we don't need Scald to burn anymore, we want to kill. Some damage calculations here:
252+ Atk Parental Bond Mega Kangaskhan Double-Edge vs. 240 HP / 140 Def Milotic: 168-199 (84 - 99.5%) -- guaranteed 2HKO
252+ SpA Mega Charizard Y Solar Beam vs. 240 HP / 96 SpD Milotic: 136-160 (68 - 80%) -- guaranteed 2HKO
252 SpA Life Orb Thundurus Thunderbolt vs. 240 HP / 96 SpD Milotic: 151-179 (75.5 - 89.5%) -- guaranteed 2HKO
252+ SpA Ludicolo Giga Drain vs. 240 HP / 96 SpD Milotic: 84-102 (42 - 51%) -- 2% chance to 2HKO
252+ Atk (M)Salamence Double-Edge vs. 240 HP / 140 Def Milotic: 84-99 (42 - 49.5%) -- guaranteed 3HKO
+2 32+ SpA Milotic Hidden Power Electric vs. 0 HP / 0 SpD Mega Charizard Y: 92-110 (60.1 - 71.8%) -- guaranteed 2HKO
+2 32+ SpA Milotic Ice Beam vs. 36 HP / 116+ SpD Thundurus: 146-174 (91.8 - 109.4%) -- 56.3% chance to OHKO
+2 32+ SpA Milotic Hydro Pump vs. 40 HP / 0 SpD Hitmontop: 130-154 (100 - 118.4%) -- guaranteed OHKO
+2 32+ SpA Milotic Hidden Power Electric vs. 0 HP / 0 SpD Gyarados: 204-244 (120 - 143.5%) -- guaranteed OHKO
This one can surprise your enemy:
Milotic @ Weakness Policy
Ability: Competitive
Level: 50
EVs: 240 HP / 4 Def / 32 SpA / 232 SpD
Modest Nature
IVs: 30 SpD
- Hydro Pump/Scald (because on an hypothetical +4 you always need to hit)
- Ice Beam
- Hidden Power [Electric]/Recover (if your team has Electric support)
- Protect
This set needs a bit of support in order to work better: Arcanine and MegaManectric are the best supports because of Intimidate (we don't have much physical defensive bulk) and SNARL to reduce opponent's SpA, cause you want to be hit by a supereffective move in order to reply with a +2 attack. A Special bulk is needed because of Electric and Grass moves are mostly special. If your enemy activates your Competitive and Weakness Policy boost then you have a +4 Milotic.
