Playstyle
I see Sceptile as a zoner--someone whose abilities lie in limiting what opponents can do and putting them in uncomfortable situations. His niche lies in that he's more skilled than your typical zoner at shutting down projectile campers...at the cost of being vulnerable to rushdown-heavy opponents who get in his face easily.
Special Moves
Standard Special: Energy Ball
A (relatively) new move in Pokemon canon, Energy Ball draws power from surrounding plant life, presses it into a sphere, then fires it at a target. At a respectable 90 base power and a 10% chance to cut its target's Special Defense by a third, it's the strongest Special Grass move that doesn't have some kind of drawback. While the move isn't
inherently associated with Sceptile, the Treecko line is one of only a few to learn Energy Ball naturally.
In Smash Bros., Energy Ball is a charged projectile with a twist. Its size is rather small--at full charge it's no bigger than a minimum-aura Aura Sphere, even though it takes just as long to charge, and its knockback is moderate at best. But its strength lies in how its effect carries over from the games: an opponent struck by a thrown Energy Ball will glow dark green for up to 8 seconds as its defenses are lowered. If they're hit when in this state, they take 1 1/3 times the regular damage!
Side Special: Leaf Slicer
It may no longer be a signature move, but Sceptile is heavily associated with Leaf Blade thanks to the built-in ones on the Grass-type's forearms. At 90 base power and a doubled crit rate, it's a force to be reckoned with...even though Sceptile's strength lies more in elemental attacks than physical ones. For this technique, Sceptile uses them a little...differently.
As the command is pressed, Sceptile crosses his arms to prepare to strike, then with a brief delay, he snaps forward not unlike Fox Illusion, ending in a quick slash that sends him into freefall.
...But if any weak projectiles get too close to Sceptile during the move's duration, he swings early and
slices clean through them, destroying them on the spot! If he destroys any projectiles in this manner, he won't slash at the end of the move, but he will
not enter freefall afterwards!
Up Special: Pursuit
A normally-weak Dark technique, if Pursuit is used when an opponent tries to switch out of battle, it interrupts them and hits with twice its usual strength! The Treecko line gets the hang of it pretty early, anywhere from Level 16-18 depending on the form that learns it and the game it's learned in.
In Smash, Pursuit turns into a recovery move with a twist. After a bit of startup, Sceptile air-dashes diagonally upward, leaving a thin trail of darkness in his wake and damaging anyone caught in the path. Anyone who lingers too close should beware, though...because at the very end of the move, pressing B again will make Sceptile perform a second, shorter but
significantly faster dash straight at an opponent if they're in range! If it connects, Sceptile does
not go into freefall and can use Pursuit again! But be sure your target doesn't dodge...
Down Special: Grass Knot
Those who've ventured through Sinnoh might know this as the gym leader Gardenia's signature move. Grass Knot causes the ground below a target to sprout without warning and snare them, and the heavier the trap's victim is, the more damage it deals. While only two lines learn it naturally, Grass Knot has a wide distribution via TM 86 that includes all Grass types.
In its Smash counterpart, Sceptile places a forelimb on the ground, summoning a small but clearly visibly clump of grass. If an opponent touches it, it springs up and snares them, dealing greater damage the heavier its victim is and causing them to trip! There're a few caveats, though: Sceptile can only place one Grass Knot at a time, they wither up after a while, and they can only be placed on solid ground--no floating platforms.