...what's this I see?

Quote Originally Posted by WindStruck View Post
Leaves to Lacquer
2nd-level Transmutation

Casting Time: 1 action
Range: touch / 20 feet
Components: V, S, M (an empty caterpillar cocoon)
Duration: 24 hours

Gathers nearby live foliage to to encase one touched object with a volume of no more than 1 cubic foot. The plant material transforms into a tough, resilient, waterproof, and airtight coating that protects the object. The object is granted +10% temporary HP (rounded up), +5 AC, and gains resistance to acid, ice, lightning, and sonic energy types, so long as at least one point of temporary HP remains.

At Higher Levels.
When you cast this spell using a spell slot of 3rd level or higher, each spell level above 2nd increases the total volume affected by 1 cubic foot, increases the bonus to AC by 1, and grants an additional +10% more temporary HP.
Couple of procedural things: I'd say the range for this is just '20 feet' (most official spells are done in 30-foot increments, but that's not a major issue), while specifying that you have to touch the object to be lacquered in the text of the spell. And 'ice' and 'sonic' are called 'cold' and 'thunder' now.

Onto the actual spell... it's pretty cool! One thing I would say is that, although the 5e DMG does provide rules for object HP and AC, they're buried near the back and sort of handwavey anyway. It might be wise to word the spell in a way that can be applied easily even if the object's statistics aren't known. I'd say something like a flat 5 THP and AC fixed at 16 (as Barkskin), increasing by 5 and 1 each when cast at higher levels.