Sitting in wait on Eupatorium serotinum. This species of ambush bug can change its hue between pale white and yellow (much like Mecaphesa sp/crab spiders). It often takes on the yellow form in late summer and fall (in order to match the yellow wildflowers of the season).
I decided to keep an eye on this one as it wasn't exactly blending in with the white boneset in my yard. It took around a week, but it slowly transitioned to the hue below:
''Phymata fasciata'' is a species of ambush bug in the family Reduviidae. It is found in Central America and North America.