Good idea. Let me adjust :-)
Recipes are really not to be destroyed after use. They can cost like 5k each from the alchemist, whether it's Paracelsus or a random encounter.
The limiting material would be crafted from the bosses. Say the questline would go like this:
1. You farm Stahl's soul, Mother's soul (lol), Klutus's soul etc., and craft them into an Ydra Ghost Summoning Parchment, etc. It should not be tradable.
2. You craft the summoning parchment with 1 or 3 or 10 elite golden chests from that season into the unique ingredient, say Ydra bacteria, huh. This is tradable.
3. You combine the Bacteria with several eggs and gold into a new pet.
Say the Ydra Bacteria will merge Flap Jack, Bop-Bob and Meep-Moop into an awesome Dodo.
You could also combine all 5 Summoning parchments into Arcane bacteria, that's why the parchments should not be tradable. If the arcane pet is comparable to Hammerjaw, the plat players should be able to swallow the existence of a free arcane pet. The bacteria crafting should however need a substantial amount of chests, to keep the price at least in 5m+ range.
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