I recently saw a screenshot from Facebook of a mattress ad presented inline in a page load that had two conventionally attractive normal looking (fully clothed, not immodest at all) women on a mattress. Below it was somebody's grandpa writing a message basically to the effect of "hello sexy ladies I am (name) please chat with me".

It possibly could have been a bot, but I don't think bots commonly use profile pictures of dishevelled looking 75 year old men. Maybe for commenting on political agitprop, they do...