Acid Trap

You press a magical rune somewhere into an object or area and create a trap that triggers on touch.  Until the spell ends, the acid trap is affixed to a 5-foot square or a medium or smaller object.  Any creature within 10 feet of the affected area or object when a creature touches it must make a Dexterity saving throw or take 1d10 acid damage.  If inspected before touching, a creature can discover the nature of the trap.  Triggering traps can be avoided if they are known to exist.

The spell's damage increases by 1d10 when you reach 5th level (2d10), 11th level (3d10), and 17th level (4d10)