Is it a new candy sensation? Thank goodness no! It's actually a rather sinister story reported in the Billings Gazette. Recently someone left a large peanut butter jar filled with water and mussels in front of the offices of the Charles M. Russell National Wildlife Refuge in Montana. Testing revealed that the water contained several stages of zebra mussels (Dreissena polymorpha), and likely came from a source where there are well-established, breeding populations of the mussels. The odd thing is that Montana doesn't have any known infestations of that species - the closest site is in North Dakota. No one has any idea why someone would bring the jar to Montana and leave it where they did, but the sample is currently being searched for fingerprints or other information that will help uncover the mystery.