Looking up where to find this item, it should be on the Adult(Buffalo, Grendel, Kookabura, Cougar)
But none of these have it on their drop/spoil list.

Where is Forgotten Scroll: Create Item - Level 10 found?

you need to buy gold food for pets and grow a pet by feeding it food, like up to level two, and then look at the drop list

Ok, the spoil list changes as they progress through the stages, thank you!