Binding Flame-Chain

You summon and lash out with a fiery chain that binds a creature in place, wrapping and scorching it. 

You can target a creature of a size Large or smaller and force it to make a Strength Saving throw against your spell save DC. On a failure, the target becomes Grappled, Restrained and optionally takes 4d6 fire damage when it starts it's turn until the spell ends. On a success, the spell fails.

Using a Higher-Level Spell Slot. For every level the spell is upcast, the fire damage increases by 2d6. For every two levels, the number of creatures you can target increases - e.g. at 6th level you can target two creatures, at 8th level you can target three creatures.