A Helio is an enemy that appears in Super Mario RPG: Legend of the Seven Stars. They are small, orbs of fire that can be found in Barrel Volcano during the fight with Czar Dragon.
Helios can only be summoned into battle by the Czar Dragon. Helios themselves only attack by dashing or exploding at one of Mario's party. They are not capable of any other special attacks.
Helios are weak against ice moves meaning Mallow's Snowy is very effective on them. However, this is not required as Helios have very low HP and can be taken out by any damaging move.