I got a fusion with an item in it? That heart thing?

I made a Unicorn that ended up having something in it.. I have leveled it 3 times already and I still haven't gotten the item. It was a real pain too since it was a priestess and I can't get the social link for that yet.
How much more do I need to level it and what type of item could it be? I haven't been able to find any of this info online. I would appreciate if someone could tell me about it?

Has anybody else ever managed to full-fill one of Elizabeths monster requests? Like the Grave Beetle one.. I killed 3 Grave Beetles after taking the request and 2 days before the deadline was up and NOT once did I get a beetle shell. Those damn rare monster's NEVER show up when I have taken her request for them. Its really annoying.