Doubles NU Threat: Wailord (By finally)

Wailord		Water Type	170 HP / 90 Atk / 45 Def / 90 Sp.Atk / 45 Sp.Def / 60 Spd
Abilities	Water Veil 	(This Pokemon cannot be burned. Gaining this ability while burned cures it.)
		Oblivious	(This Pokemon cannot be infatuated or taunted. Gaining this ability cures it.)
		Pressure	(If this Pokemon is the target of a foe's move, that move loses one additional PP.)

Even with Wailord's fantastic HP stat, its pitiful base 45 defences do not lend this giant pokemon towards a bulky offensive role on your team. The main reason to use Wailord in Doubles NU is it's access to the powerful spread move Water Spout. Thanks to its base 60 speed stat however, Wailord will need some form of speed control in place in order to use Water Spout to the fullest. Unfortunately for wailord, there are a few electric types that outspeed scarfed Wailord, and there are some pokemon like Seismitoad and Jynx that are immune to Water moves. - KyleCole

Choice Scarf
Wailord @ Choice Scarf
Ability: Water Veil
EVs: 252 SAtk / 4 SDef / 252 Spd
Timid Nature
- Water Spout
- Scald/ Hydro Pump
- Ice Beam
- Hidden Power [Grass]/ Hidden Power [Electric]

Wailord may not look very threatening from the start with only his massive hp stat to make him stand out from the rest. But what makes wailord a major threat is his access to water spout. Water spout in conjunction with wailord’s respectable bulk allows him to blast off huge water spout damage to both enemies. After losing some health, you can switch to scald or water spout. Scald will have the same or greater base power at 71% while hydro pump will have the same or greater strength at 98%. This is because scald and hpump target a single target and do not have to be at .75 power like double targetting water spout. The hidden power is whatever the you want it to be. idgaf, go wild. - finally

Kyle Edit: Hidden Power Grass lets Wailord hit incoming seismitoad for a clean 2HKO, while HP Electric gives Wailord the OHKO on 252 HP Pelipper 56% of the time if modest, 6% if timid.
Forming a Fire/Water/Grass core with Wailord is an excellent way to fit Wailord onto a team, with a grass type like roselia or cacturne to take out bulky waters (particularly seismitoad) and a fire type like camperupt to take care of jynx and electric types. Rain Dance users like Electrode or Volbeat are also great teammates, with rain giving a much needed power boost to Water Spout.

Scarf is the best set in order to ensure that you hit first. If you hit first, your water spout will be stronger. Timid is because wailord is slow mode. Alternatively you could run speed support on your team and not be scarved wailord. Options would include tailwind, icy wind, twave, and trick room. Trick room would probably be the best out of those to abuse wailord’s naturally lowish speed.
A tr set would be like this -

Slowlord (Wailord) @ Choice Specs
Ability: Water Veil
EVs: 128 Def / 252 SAtk / 128 SDef
Quiet Nature
IVs: 0 Atk / 0 Spd
- Water Spout
- Hydro Pump
- Ice Beam /Hidden Power [Grass]/ Hidden Power [Electric]/ Hidden Power [Fire]
- Protect

wailord already has all the bulk in the world. it lives the hit.

Teammates: Almost all the follow me users and rage powder users to redirect attacks from wailord while he spews water spouts. Parasect gets a special shout out because he redirects and resists grass and electric hits. Also, he can put stuff to sleep that wailord can’t handle. This core is especially deadly in a trick room setting as the two are both pretty slow.

Wailord hates fighting things that are faster than it and can weaken it’s water spout. It also hates when you turn its speed against it. So if you are fast wailord, when opp sets up tr or twaves you. If you are slow, when opp is just plain fast. Most water types match up against wailord pretty well, as hidden power does pretty pitiful damage. So stuff like phione, walrein, qwilfish, and lanturn.
All in all, if you want an addition to your rain team or you just wanna spout on something, wailord is your dude. The scarf set does not need as much support as the tr set, but the tr set probably puts in more work.
im tired, just use it yourself and see what it’s like. -finally

Kyle Edit: The coverage move is all up to you, thanks to Choice Specs and a Quiet nature, Ice beam will get the OHKO on Altaria, HP Grass will OHKO Seismitoad, HP Electric will OHKO Pelipper, HP Fire will always OHKO 252 HP Parasect, and will OHKO 252 HP 252+SpDef Parasect 56% of the time.
Lampent makes a great partner for this set because it can set up Trick Room and discourages grass types from switching in. Rhyhorn is also an interesting partner because it can function in Trick Room, and has access to Lightningrod to draw away electric attack from Wailord. Rhyhorn also has access to Bulldoze, meaning that it won't be forced to use Earthquake to defeat opposing electric types.

Other Options
Choice Specs gives Wailord a huge amount of added power, but without speed control like Tailwind or Trick Room, Wailord is going to take hits before firing off Water Spout which reduces its power. Simply not running Water Spout is a bad idea because Wailord becomes outclassed by the various other available water special attackers in Doubles NU. Wailord has access to a strong physical movepool with Waterfall, Earthquake, Heavy Slam, Body Slam, and Avalanche, however it is outclassed in this regard by faster and stronger physical water hitters like Samurott and Floatzel. An Assault Vest set or a Curse set both look viable however whichever you choose will leave Wailord's other Defensive stat vulnerable. - Kyle Cole

Checks & Counters
Bulky water types like Mantine and Alomaloma take little damage from any of Wailord's attacks, Mantine must be wary of HP Electric however. Jynx and Seismitoad are immune to Water Spout but Seismitoad has to worry about Wailord carrying Hidden Power Grass. Electrode and Zebstrika outspeed the Scarf set naturally and can OHKO with powerful Electric STAB moves. Grass types in Doubles NU can switch into Wailord's Water Spout but must be wary of Ice Beam as nearly all are 2HKO'd by the specs variant. Wailord also suffers from predictability, essentially having 1 moveset so a smart opponent will generally be able to play around you. - KyleCole