I have an idea for the mod described as above. Basically, it would be a peace deal option which changes the country's colour to brown for 10 years, and gives the capital a 'smeared in ♥♥♥♥' modifier. -80% production and -80% trade power for 2 years. 100% warscore cost. Alternatively, it could be a covert operation, and if the target discovers it they get a ♥♥♥♥ smearing cb.