A guildmate pointed this out to me, and I thought it deserved attention...
The common crown crate reward 'Crown Survivor's Elixir' is uncraftable. This potion:
- Heals
- Provides invisibility
- Grants unstoppable, and (claims to) automatically break free on use.
A potion with restore health, invisibility and immovability is craftable (Namira's rot, Columbine and Blue Entoloma), but does not break free on use. I can confirm that the crafted version does not automatically break free on use (tested against Bittergreen the Wild), but I'm unwilling to actually test the crown crate reward; I'm not paying real money just to test this game.