Random, you get a Spiritomb, which must learn Toxic ASAP, and KO three E4 Pokemon with Toxic damage alone. It can only ever know one offensive move. Must solo every Pokemon in the entire game.
On to mine:
LightSabre's Lapras
-Lapras named Commander
-must have Curse bred onto it, and use the move 3 times every battle it's in, including wild fights(not required to be immediate). He must keep this move
-No Physical moves, must be all special attacks
-Other than Surf, other two attacks must have < 90 accuracy
-Must solo 300 trained pokemon
-Must solo every Gym pokemon that isn't taken by a different challenge
-Must solo Lt. Surge and all trainers in the gym
-Must be the highest level pokemon on the team
-Must solo RED's Lapras and all remaining pokemon of RED's
I like this challenge. 300 might be tough, but we'll see. Predicted VVP (Very Valuable Player)
kipp's Bellsprout
Take a Bellsprout. It may only learn one move of each kind (Physical, Special and Other). These can be replaced anytime, but it may only know THREE MOVES. Solo Falkner to evolve, Jasmine to evolve again.
I think I may just designate one move as unusable, and keep it for the whole game. I doubt it will be too helpful.
Geckoboy's wtf challenge
You'll have to check this one out yourself.
Oh my God. When I finally work out what is going on here, I'll decide how to proceed. We'll see.
Sprocket's Geodude
You get an all-special male Geodude, caught in Route 46 as soon as you get your first set of Poke Balls, before your battle with Falkner. It cannot use physical moves, in or out of combat, for any reason --- this includes HM moves! It cannot evolve to Graveler unless it can solo Whitney's Miltank and Morty's Gengar (no restrictions to evolve to Golem). You may not trade it to teach it moves on another game pack, or EV train it, until it evolves to Graveler or Golem. Most importantly, it must solo Red's Snorlax.
A Geodude which can not use Physical moves, and is not even useful as an HM slave. Hmph. And interesting factoid for everyone: Geodude learns no special moves by level-up.
Breludicolo's Chikorita
Athendoros, you get Derp the Chikorita. Derp is very derpy; thus it cannot ever use an attacking move after level 9, when it must learn Poisonpowder. Tackle and Razor Leaf must be replaced posthaste.
Any non-attacking moves are fine to use. The Chikorita may be transferred over with Leech Seed bred onto it (lvl 5) or the TM06 Toxic may be transferred over.
Can't transfer, so this is going to be bad. Fortunately, no soloing challenges as yet, so predicted LVP.
Texas' Charmander/Wooper
Since I believe you have 1 left, if you can trade, take the Charmander found on page 88 or in my sig. Solo Lance and Blaine.
If not take a Wooper. It may never know Water, Ground, Ice or boosting moves. Solo Lance and Blaine in order to evolve. KO 3 pokemon in the rival dual battle and 1 of Red`s pokemon anyway, it or your rival`s pokemon are the only pokemon allowed to inflict damage.
I can't trade, but I could pick up a Charmander later in the game, and so still fulfill the requirements. I may do that. Fortunately, still no solos prescribed.
So that's all of them. You can still put in more restrictions if you want, to make them harder, because I am still looking for the hardest thing so far.