Answer: Entamoeba coli cyst
The distinguishing features are the size (greater than 15 microns, although smaller immature forms may be seen), and most importantly, the number of nuclei (>4).
Significance to host: Tom said it well "Finding this organism means that the person was potentially exposed to less-than-ideal sanitary conditions at some point, and could be at risk for other pathogens passed under said conditions. This E. coli is probably not causing any damage to the host, and hence would not be considered a pathogen."
I particularly like Patty's comment:
OMG! I know this one! I agree with everything Tom said above and I'm thrilled that you gave us an easy one this week.
Actually, looking at iodine stained wet preps can be quite challenging, so Good job everyone!