Barkskin

2nd-level transmutation
Casting time: 1 action
Range: Touch
Target: One willing creature in touch range
Components: V S M (a handful of oak bark)
Duration: 1 hour
Classes: Druid, Ranger

You touch a willing creature. Until the spell ends, the target's skin has a rough, bark-like appearance, and the target's AC can't be less than 17, regardless of what kind of armor it is wearing.