This is a new Defensive core I've been testing, I needed something that could consistently counter & check Sub Bulk Up Braviary and still be usable on a regular team and this is what I came up with. This Core also makes a good Cinccino check (the current most used pokemon in the tier).
Weezing and Probopass cover each others weakness quite well. Probopass resist Weezing's only weakness to Psychic while Weezing resist Probopass's Fighting weakness and is immune to Probopass's ground weakness, the only exception is the rare Mold Breaker Pinsir with Earthquake.
This core isn't perfect with a vulnerability to special water types such as Gorebyss, Ludicolo and the odd Samurott so a water resist or immune partner to this core is appreciated, examples are Re-generator Alomomola, Water Absorb Seismitoad, Ludicolo... etc, basically a solid water, grass or dragon type but be-careful of ice moves.
Another problem with this core is lack of reliable healing as they both are reliant to on Painsplit so a Wish user helps the core a lot, Alomomola is a good partner as she takes care of this core water weakness and can pass wishes. Other Options are Audino and Lickylicky etc...
Another Pokemon that can break this core is the uncommon Stunfisk as he attacks on the special side easily dispatching Weezing and Probopass having a quad weakness to earth power.
Weezing @ Leftovers / Black Sludge
Trait: Levitate
Evs: 252HP/252Def/4SpAtk
Nature: Bold
-Will-o-Wisp
-Pain Split
-Sludge Wave / Sludge Bomb
-Thunderbolt / Clear Smog / Haze
The set used for walling physical threats and while having the option to punish switch in that is core is weak too. Pain split and will o wisp is the bread and butter of this set for physical walling. Sludge bomb/Sludge Wave is for the mandatory stab. Sludge wave is preferable for the extra power but I've gotten lucky from the poison damage before. Thunder bolt is really only there to punish water types switch in that can dismantle this core while Ludicolo is still hit hard by Sludge Wave. Clear Smog & haze can be used if you don't want to be set up bait for sweepers.
Although Weezing is a good defensive wall, it can be easily 2hko by come choice band user such as Rampardos or Guts/Toxic Boost pokemon such as Ursaring and Zangoose so be wary of them
Probopass @ Leftovers
Trait: Sturdy
Evs: 252HP/252SpD/4SpAtk
Nature: Calm
-Power Gem
-Toxic / Thunderwave
-Volt Switch
-Pain Split / Stealth Rock
Power Gem is the main choice of Stab to check Sub Bulk Up Braviary, Thunder wave or Toxic depends on what status your team needs. Volt Switch again is there to deal damage on predicted Water types switch ins and to keep your momentum. Pain split is a option keep your Probopass healthy. Stealth Rock is there if you don't have any other member to set it up.