For Wool of Bat I used some fake fur that Teen2 had lying around. I just snipped it into little chunks and suddenly I had bat fur.
This is an idea I found on the Internet. You take a little plastic skeleton, wrap some spider web stuff around it, bent it into an awful position, immerse it in colored water and make a disturbing label. Mine says: Shrinking Potion Trials, June 1867, Test Subject No. 013, Healthy Male 22 years, Survived 2 days, 14 hours. The idea came from this wonderfully creative person who just happens to have some other great ideas I'm going to use too.
Here are more strange things from the garden. I think these are quince, but I'm calling them Datura stramonium. I know, I know, actual Thorn Apples are spiky little seed pods, but I'm hoping no one else will know that.
Oh, and this one was fun. It's a little yogurt, some lemon curd and some chunks of strawberry jam with green food coloring. The red jam chunks make a nice surprise when you pick it up and inspect it.
For the labels you can snag images off the Internet and rearrange them in Photoshop like I did, or you can use felt pens and write your own. But whatever you do, make sure you antique them like I showed you here. Have fun with this, but be careful! You're messing with magic you know!