Robe of Shards 2014

Deep Magic: clockwork You create a robe of metal shards, gears, and cogs that provides a base AC of 14 + your Dexterity modifier. As a bonus action while protected by a robe of shards, you can command bits of metal from a fallen foe to be absorbed by your robe; each infusion of metal increases your AC by 1, to a maximum of 18 + Dexterity modifier. You can also use a bonus action to dispel the robe, causing it to explode into a shower of flying metal that does 8d6 slashing damage, +1d6 per point of basic (non-Dexterity) AC above 14, to all creatures within 30 feet of you.