I thought this might be a motor start or run capacitor based on its size, but its markings aren't particularly revealing (to me).
Also I'm not sure if the resistor would be typical on a motor capacitor?
Unfortunately the stamped markings seem illegible, its not due to being a blurry photo (3rd image).
C800 (or C-800 or C•800) KS 2018-1 CORNELL-DUBILIER <patent #s> NAF
As noted in a comment, its 4.7MΩ.
It's about 2x3 inches (50x75 mm).