Slaking's full power with Traunt?

Question

Apprently people say Giga impact is much better on this king because of Traunt. Is that true?

And can you make a leftovers set with Giga Impact..?

Answer 1

The reason why Giga Impact is used on Slaking so frequently is because Truant will cause you to miss a turn anyway, so you might as well go for broke and use the most powerful STAB move for Slaking.

As for a set, Slaking is never suited for leftovers. It's meant to attack, not tank considering it can't do anything every other move.

Slaking @ Choice Band
Ability: Truant
EVs: 252 Atk, 252 HP, 4 Def
Nature: Adamant
- Giga Impact
- Earthquake
- Hammer Arm
- Retaliate/ Night Slash

That's for a bulky Slaking. If you want a revenge set:

Slaking @ Choice Scarf
ABility: Truant
EVs: 252 Atk, 252 Speed, 4 HP
Nature: Adamant
- Retaliate
- Earthquake
- Hammer Arm
- Night Slash

Answer 2

Giga Impact is good on Slaking since traunt makes it so it cant move every other turn anyway.

Slaking@Choice Band
Adamant
252atk 252 hp 4 def
Traunt
-Giga Impact
-Earthquake
-Fire Punch
-Night Slash

Giga Impact will destroy anything that doesnt resist it. Earthquake is for Rock and steel types while Fire Punch is for Coverage + Ferros and Scizors. Night Slash to deal with ghost types.