It's Body slam disides it

Another classic speed vs. power matchup. This battle could go either way, really. Looking at their attacks. Meganium's Vine Whip and Body Slam combo would be deadly, and sure to finish off anyone. However, Quick Attack and Leaf Blade, combined with Sceptile's precision, will be huge trouble for Meganium. Edge: Sceptile.

yea i'd have to agree with coolnala on this this one.

Sceptile all the way! More speed and attack. Meganium is just too slow, should only be a physical wall. That's it.

Meganium has some strong attacks like Solarbeam which can really affect any kind of Pokemon. Sceptile's speed ability is definitely an advantage! Its like Ninja skills! I go with Sceptile but it would be really an interesting match to see!
(sucks that in the anime, Ash's Sceptile lost to Tropius for that Meganium.)

^what happened in that episode was lol worthy, truly terrible plot for Sceptile. If he could've attack properly he would of beat that Tropius easily. However couldn't of Ash got Sceptile to use moves that doesn't focus on body alteration, leaf blade, or long range, bullet seed, like Slam?

On-topic: Sceptile has the advantage of speed and power while Meganium is just a wall as stated. I don't he him having much trouble beating her.

Yeah, with proper attacks Sceptile could have definitely won! Though i really have to rewatch the battle to found out what exactly went wrong! And also, i remember Sceptile was not able to attack Bullet Seed :/ idr and idk, why it was not able to attack at that moment :|

I know it had something to do with him being heartbroken by Meganium but the specifics are blurry. IMO he could of beat that Tropius with just slam, his strength in that attack was quite good iirc.

Yeah Sceptile is no doubt one of Ash's strongest Pokemon! And yeah, he was heartbroken but that should not have affected his Bullet seed! Lol
he could have took revenge instead of being a silly!
And also, he then just evolved from Grovyle, i was definitely expecting to see some awesome moves but ended up seeing some unexpected! XD

I believe it shouldn't of either, poor story writing right there.

Could be a trend for Ash's powerhouses:
Charizard wouldn't obey him until he proved himself
Sceptile couldn't attack properly due to being heartbroken
Grotle couldn't adapt his loss of speed
Chimchar/Monferno/Infernape lack of control with Blaze

^ lol. nice one! But Ash and his Pokemons are still cool =)

Note: The Meganium in this particular case is Casey's, who is male.

I think it could go either way but I think Juptile would win.