Having him only 3 months, you may just now be seeing his real temperament, be aware of that.
Is Casper a rescue or did you get him from a breeder? Do you know any of his history?
With this happening in the evening, was this inside or outside? Was Mr. R wearing a coat and/or a hat? If evening and outside, the lighting is different and if Mr R was wearing a coat, his silhouette would be different. I'm wondering if that has something to do with it?