Tri-Attack

You combine the three elements of fire, frost, and lightning into a fierce strike.  Make a melee spell attack against a creature you can reach.   If it hits, the target takes 1d10 cold, 1d10 fire, and 1d10 lightning damage.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d10 for each slot level above 1st.  Choose whether the additional 1d10 is cold, fire, or lightning damage.  However, a type of damage can not be more than 1d10 less than the other two.