User:Missingno. Master/Glitch Pokémon Reviews
This page gives detailed reviews on various Glitch Pokémon and their usability in competitive battle.
Missingno., Missingno., Missingno.. Look at its stats. Its massive Attack stat is the highest out of any Pokémon in RB. Then again, its Speed is the LOWEST out of any Pokémon in RB. Difficult to pull off anything with this classic, but well worth it. Thunder Wave is for paralysis- in the speed department, Missingno. needs all the help he can get. Note that it can only learn Hyper Beam through the Rhydon trick. Submission is powerful, as is Earthquake. Not much to say here, really, except try to use this with some confusion/sleep support.
It is famed for knowing Sky Attack, but don't be tempted. That's basically asking for something to murder you while charging. Fly would be preferable, but most people could just KO it with Swift, or else switch to their Onix. It learns Substitute and 'M (00) doesn't, but again, too slow to pull it off.
.4's stats aren't too bad, actually quite impressive. Its Attack and Speed stats are pretty OK at 95 each. And 209 in Defense and 179 in HP allow it to be pretty defensive as well. The only thing letting it down is its low Special stat, which seems to be a pattern amongst pure Glitch Pokémon. Agility is there for the benefit of your speed. Thunder Wave for paralysis support. For sweeping, there's TM28 and Hyper Beam (just beware of TM28's iffy accuracy).
Like Missingno., it learns Sky Attack, and this time you actually may want to consider it, because .4 actually has a chance of surviving the charge turn. Just beware of high-defense switch-ins. Toxic could go well over Thunder Wave, as Thunder Wave's speed drop is rendered pretty redundant next to Agility. Given .4's defenses, Counter could work, but as in RBY it only deflects Normal and Fighting moves, this is very situational. Dragon Rage-big no-no. It only chips away 40 HP at a time, and you can't really afford to do minimal damage each turn, especially against some high-HP beast wielding special attacks, like Chansey. If you're a gamblin' type, try your luck with TM05, which ups Evasion by TWO stages. .4 doesn't learn Double Team, but with TM05, WHO CARES?!
What we have here is a Glitch Pokémon with crap stats in everything except speed, in which it excels. Notably, A is the only Glitch Pokémon to learn Transform (with the possible exceptions of Missingno.'s ghost and skeletal forms). That's the main move here, as once A transforms, it loses its crap stats and gains its opponent's stats! And it has the speed to transform before it takes a hit. One-hit KO moves in RBY only hit if the user is faster than the opponent. A will probably be speedier than anything else, so Guillotine and Fissure are good options. Seismic Toss can give you something to finish off those low-HP opponents.
It can learn Reflect, but good luck using it and living. Even after Reflect is used, A's defense will still be pitiful. Counter sounds promising, but not with A's defense and HP. Don't even consider any attacking moves, with A's base 0 Attack.