Brambleskin

You touch a willing creature. Until the spell ends, the target's skin poofs out shrubbery a good half-foot from their body. More importantly, the target's AC can't be less than 18, regardless of what kind of armor it is wearing. (This spell is not concentration.) 

However, due to the bramble, if moving more than half your normal movement speed, you take 1d4 damage per 5.ft of movement (with the exception of falling). Any melee attacks are made with disadvantage. 

Melee attacks have a chance to have a ten percent chance for the weapon or limb get stuck in the bramble. As an action, a successful DC 15 Athletics or Acrobatics check will remove the weapon or appendage. 

Healing spells (not cantrips) on the target bring forth 1d4 goodberries.