Benjamin's Burrowing Blast

A small line of fire springs from the caster's hand and burrows into a target within range, on a hit the target takes 4d6 fire damage. After a few moments a small mote explodes on the target, and the target has to make a strength saving throw against the DC of the spellcaster. If the target fails the saving throw, their speed is 0 until the beginning of the next round. This spell can be cast as a reaction when a creature moves towards the spellcaster, and as an action on the spellcaster's turn.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 for each slot level above 1st.