Is Grass knot on Heliolisk Worth it?

Question

Reason why I ask this is because is because Heliolisk is a good special sweeper, but has nothing for gastrodon and swampert. Also if it's not please tell me a move that would replace it for Heliolisk.
Just an so you know it has hyper voice, thunderbolt, and surf. And has dry skin

Answer 1

I would say, Yes
It seems like a great move to predict switch-ins, although you might be better off getting rid of Surf for Dark Pulse.

With the Moveset of
-Thunderbolt
- Grass Knot
- Surf
- Hyper Voice
You can hit 15 Pokemon "Not Very Effectivly" (Mostly being Ghost type Pokémon)
You can hit 447 Pokemon with "Normal Effectivness"
You can hit 315 Pokemon for "Super Effective" damage

With a Moveset of
-Thunderbolt
- Grass Knot
- Dark Pulse
- Hyper Voice
You can hit 0 Pokemon "Not Very Effectivly"
You can hit 446 Pokemon with "Normal Effectivness"
You can hit 332 Pokemon for "Super Effective" damage

So I would recommend:
Heliolisk @ Life Orb
Ability: Dry Skin
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Thunderbolt
- Dark Pulse
- Grass Knot
- Hyper Voice

Life Orb to hit things extra hard combined with rain recovery from Dry Skin is pretty reliable

Comments

hope I didn't go too much off topic....

Answer 2

I think grass knot is a great option for heliolisk to deal with pesky rock types as well as the gastronomic and swampert discussed earlier. Hp ice is another good move but since you have surf your coverage is already amazing. Good luck.