Beedrill

Swarm
Boosts power of Bug moves 50% when at 1/3 HP or less.
Type Tier
Bug / Poison NU
Statistics
Min- Min Max Max+
HP
65
- 271 334 -
Atk
80
176 196 259 284
Def
40
104 116 179 196
SpA
45
113 126 189 207
SpD
80
176 196 259 284
Spe
75
167 186 249 273
Name Item Nature

Choice Bander

Choice Band Jolly
Moveset EVs
~ Sludge Bomb
~ Hidden Power Bug / Hidden Power Rock
~ Brick Break
~ Double-Edge / Twineedle
4 HP / 252 Atk / 252 Spe

Choice Band set, probably the best you will get with Beedrill on most teams. He can't really damage much and cannot switch into anything without a prediction, but he is faster than stuff like Breloom... Only use Twineedle if you really want Hidden Power Rock to hit Fliers and other Bugs, as Twineedle isn't that powerful. However, it does have that nice ability to Poison things, even Steel types.

Name Item Nature

Swords Dancer

Liechi Berry / Salac Berry / Scope Lens Jolly
Moveset EVs
~ Endure / Agility / Brick Break
~ Swords Dance
~ Hidden Power Bug
~ Sludge Bomb
4 HP / 252 Atk / 252 Spe

A pathetic sweeper, this won't even survive 1 hit to setup. You'll need most of the other teams' Pokémon to be paralyzed for this to even START sweeping. Not suggesting Leftovers, this has NO sort of survivability. If you are using Salac Berry, don't use any Speed EVs in NU, but rather, pump one of the defenses or HP to try and survive a hit while you Swords Dance.

Name Item Nature

Endeavor

Liechi Berry / Salac Berry Jolly
Moveset EVs
~ Endeavor
~ Substitute / Endure
~ Hidden Power Bug
~ Sludge Bomb
252 Atk / 4 SpD / 252 Spe

If you want to use an Endeavor team and don't want to use the slowpokes (Swampert and Aggron), this could always be an option. As always, Substitute down to 1 HP and watch Beedrill do the most damage you'll ever see in its life. This is the only way to get an almost guaranteed kill out of Beedrill. Do NOT put the last 4 EVs into HP, or you will not be able to Substitute the 4th time.

EVs

Max Attack and Speed. Most of the time, 252 / 252 / 4 spreads aren't very effective, but no matter how much Defense you put on Beedrill, it won't live through anything. On the Endeavor set, make sure that the 4 leftover EVs do not go into HP, as you want to be able to Substitute down 4 times for it to work optimally. You could also run 8 HP to get down to exactly 1 HP, if you are that meticulous, but it's not necessary, and it forces you to take EVs out of Attack or Speed.

Opinion

Beedrill has bad stats all around, no real special movepool, and a poor physical one. Its typing does very little to benefit it, as well. This is really only usable in NU, where it is still outclassed by other Pokémon. The Endeavor set, for example, is just a worse Raticate.

Counters

Standard: Almost anything. Salamence, Gyarados and Metagross come in easily on about anything and tend to OHKO Beedrill, especially with a Choice Band, but they should beware of Endeavor. Suicune can phaze its stat-ups. Same for Skarmory, except Skarmory is also immune to Sludge Bomb and has 4x resistance to Bug, and can OHKO Beedrill with Drill Peck or Hidden Power Flying. Weezing resists it all too, and can Fire Blast, but even Sludge Bomb versions will fare well enough with Haze. Swampert does a load of damage with Earthquake, Surf or Hydro Pump. Basically, any Steel, Ground, Rock or Flier, except in rare cases (like switching in Tyranitar on a Bug move), will easily dispose of Beedrill with no rocket science behind it at all. Tyranitar can ruin the chances of an Endeavor set doing much of anything if you aren't careful.

In UU, Beedrill still has a hard time. Gligar, Aggron, Nidoking, Qwilfish, and Tentacruel resist or are immune to both its STAB moves and get unlimited time to set up and hit as hard as they want. Solrock resists Sludge Bomb and has STAB Rock Slide, however it is weak to Hidden Power Bug. Fearow does not like Sludge Bombs, but anything else is fair game to switch in and threaten with STAB Choice Banded Drill Peck. Golem and Sandslash's high Defense and Attack make quick work of Beedrill as well. Quagsire does about as well as Swampert does at countering. Again, in summary, Ground, Steel, Rock or Flying types do best.

In NU, Beedrill is resisted by other Poisons like Ariados and enemy Beedrill. Whiscash and Piloswine go about as easy as Quagsire and Swampert thanks to the Sludge Bomb resistance. Pidgeot and Murkrow do the same as Fearow: try to get in without being hit hard by Sludge Bomb, or in Murkrow's case, Bug moves as well, and threaten to OHKO with Drill Peck. Togetic's Defense isn't the best so Sludge Bomb might hurt, but a Hustled Aerial Ace or a Fire Blast still hurts a lot. Magcargo has great Defense and the type advantage over both Beedrill's STAB options, and can OHKO with a Fire move. Relicanth and Sudowoodo resist Sludge Bomb and Rock Slides Beedrill to death. Torkoal easily takes some blows to counterattack with a Fire move as well. Mawile has Intimidate, resists Bug, and is immune to Poison, so it can set up some stats to Baton Pass to another Pokémon, or just kill Beedrill outright.

For the Endeavor set, carefully watch your switches, and preferably finish off Beedrill with Quick Attack, Extremespeed, Fake Out (watch out for Endure) or a similar move. Killing it with a faster Pokémon and not allowing it to get in a Substitute (Rock Blast and other multi-hit moves can help with this) is generally the best way.