Horse Nettle plants are dead and dried during the winter, but their fruits can remain plump and juicy. The yellow colored, cherry tomato shaped fruits of Horsenettle could look like a meal to the uneducated forager. Their tomato looks should be a warning, though. The tomato's family (nightshade) is full of wild relatives that are harmful to humans. The Horsenettle fruits and most other parts of the plant are poisonous to varying degrees from the toxic alkaloid solanine. Eating fruits can cause abdominal pain, and possibly lead to circulatory and respiratory depression. Just remember that there are no edible wild tomatoes in the lower 48.
The classic holiday decoration of mistletoe can be found growing wild in oak treetops throughout the East. One popular way to harvest it is with a shotgun. The appealing looking white berries should be your first warning. Generally speaking, almost all white berries on earth are toxic to humans. The berries and the leaves of this poisonous parasitic plant can cause gastrointestinal problems including stomach pain and diarrhea. Mistletoe can also cause a dangerously low pulse. Kiss under it, fine - but don't eat it.