MAJOR DEFENCIVE CALCS - SNORLAX & BLISSEY
(Just a note, if "after Leftovers recovery" is not noted on :Snorlax:, it just means it did not make a difference and/or is implied and thus was left out for less text / better formatting.)






VENUSAUR
As you can see, the sheer damage reduction from Weather Ball Venusaur is nice in a general sense; even a slightly damaged :Blissey: can now be 2HKOd, meanwhile :Snorlax: can come in and stay in long enough to do something.
Of course, :Snorlax: does not fair as well as :Blissey: when defending :Venusaur:'s other attacks, but as I'll detail in the offence section, one turn more is all :Snorlax: needs.


:Venusaur:->:Blissey:
+2 252+ SpA Life Orb Venusaur Weather Ball vs. 252 HP /   4  SpD Blissey in Sun: 299-352 (41.8 - 49.2%) -- guaranteed 3HKO
+2 252+ SpA Life Orb Venusaur Giga Drain   vs. 252 HP /   4  SpD Blissey       : 224-265 (31.3 - 37.1%) -- 79.4% chance to 3HKO (37.2 - 44.1% recovered)
+2 252+ SpA Life Orb Venusaur Sludge Bomb  vs. 252 HP /   4  SpD Blissey       : 269-317 (37.6 - 44.3%) -- guaranteed 3HKO
+2   4  Atk Life Orb Venusaur Earthquake   vs. 252 HP / 252+ Def Blissey       : 287-339 (40.1 - 47.4%) -- guaranteed 3HKO


:Venusaur:->:Snorlax:
+2 252+ SpA Life Orb Venusaur Weather Ball vs. 252 HP / 252+ SpD Thick Fat Snorlax in Sun: 133-156 (25.3 - 29.7%) -- 0% chance to 4HKO
+2 252+ SpA Life Orb Venusaur Giga Drain   vs. 252 HP / 252+ SpD 	       Snorlax	     : 199-234 (37.9 - 44.6%) -- guaranteed 3HKO  (33.2 - 38.8% recovered)
+2 252+ SpA Life Orb Venusaur Sludge Bomb  vs. 252 HP / 252+ SpD 	       Snorlax	     : 235-278 (44.8 - 53%) -- 0.4% chance to 2HKO
+2   4  Atk Life Orb Venusaur Earthquake   vs. 252 HP /   0  Def 	       Snorlax	     : 226-266 (43.1 - 50.7%) -- guaranteed 3HKO






BLACEPHALON
One of the biggest roles :Snorlax: provides is the ability to completely counter :Blacephalon:.
Sure :Blissey: also is immune to Ghost attacks but doesn't resist Fire and can't fight back at all.
:Blissey: can maybe hope to damage with Toxic or cripple with Thunder Wave,
  but realistically you have to pivot into a mon that probably doesn't outspeed Scarf.
And if :Blacephalon: uses Trick then :Blissey: has to either Teleport that turn and so you can revenge kill (but now :Blissey:'s as good as dead)
  or you Thunder Wave and :Blacephalon: just spams attacks waiting for you to die or switch out.
There are even some Substitute sets running around reminiscent of the :Spectrier: days.
(With :Spectrier:, a similar issue regarding :Blissey: arose. And here as well :Snorlax: hard-countered it.
:Spectrier: could only ever disable :Snorlax:'s attack or recovery one at a time, resigning to either be stalled out or killed.
Taunt + Disable was annoying but then it couldn't Sub and hit/Toxic you.)
Look at the calcs on this; it's comedic.


:Blacephalon:->:Blissey:
   252  SpA Blacephalon Flamethrower vs. 252 HP / 4 SpD Blissey: 127-150 (17.7 - 21%) -- possible 5HKO
+1 252+ SpA Blacephalon Mind Blown   vs. 252 HP / 4 SpD Blissey: 348-409 (48.7 - 57.2%) -- 94.1% chance to 2HKO


:Blacephalon:->:Snorlax:
   252  SpA Blacephalon Flamethrower vs. 252 HP / 252+ SpD Thick Fat Snorlax: 57-67 (10.8 - 12.7%) -- possibly the worst move ever (15-21HKO?)
+1 252+ SpA Blacephalon Mind Blown   vs. 252 HP / 252+ SpD Thick Fat Snorlax: 153-181 (29.1 - 34.5%) -- 99.9% chance to 4HKO after Leftovers






VOLCARONA
Utilizing Quiver Dance and Roost, :Volcarona: is of course another pokémon :Snorlax: handles better than :Blissey:
  (of course Flash Fire :Heatran: is the best counter but that's a different matter).
:Blissey: can't do anything but Toxic :Volcarona: to do damage, as Roost shrugs off Seismic Toss and then some.
And again, Substitute Swarm sets aren't that uncommon either. Flamethrower / Fiery Dance doesn't do jack so :Volcarona: has to resort to Bug Buzz.
The worst it gets is the 25% chance or so for +2 :Volcarona: to hit you once then finish with Swarm boost.
However, :Volcarona: still has to contend with :Snorlax:'s offensive presence as I'll note later, and not that many :Volcarona: run Swarm.


:Volcarona:->:Blissey:
+2 252 SpA       Volcarona Flamethrower vs. 252 HP / 4 SpD Blissey: 232-274 (32.4 - 38.3%) -- 98.2% chance to 3HKO
+2 252 SpA       Volcarona Bug Buzz     vs. 252 HP / 4 SpD Blissey: 232-274 (32.4 - 38.3%) -- 98.2% chance to 3HKO
+2 252 SpA Swarm Volcarona Bug Buzz     vs. 252 HP / 4 SpD Blissey: 348-411 (48.7 - 57.5%) -- 94.5% chance to 2HKO


:Volcarona:->:Snorlax:
+2 252 SpA       Volcarona Flamethrower vs. 252 HP / 252+ SpD Thick Fat Snorlax: 102-121 (19.4 - 23%) -- possible 6HKO after Leftovers
+2 252 SpA       Volcarona Bug Buzz     vs. 252 HP / 252+ SpD           Snorlax: 204-241 (38.9 - 45.9%) -- guaranteed 3HKO after Leftovers
+2 252 SpA Swarm Volcarona Bug Buzz     vs. 252 HP / 252+ SpD           Snorlax: 306-361 (58.3 - 68.8%) -- guaranteed 2HKO after Leftovers