Tiberius's Temporal Spear

You hurl a spear made of condensed and concentrated time from your hand. Make a ranged spell attack against the target. On a hit, the target takes 2d8 force damage, and has its speed halved until the end of its next turn.  

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d8 for each slot level above 1st.