Backlash

A 2nd level ability of Preserver Wizards in Athas.

Beginning at 2nd level when you choose this path, you can imbue an area of land and plants with protective magic. By expending a 1st level spell slot, you can ward a circular area centered on yourself with a 20ft radius against Defiling. A Defiler who attempts to draw the energy of this land must make a Constitution saving throw. The defiler suffers 2d6 radiant damage on a failed saving throw, and half damage on a successful save. If you expend a higher spell slot than 1st level, the radius increases by 10ft and the damage increases by 1d6 for each level above 1st.