Does this sound like a creep?

I once saw one of my coworkers give some younger worker 18 hugs because it was her 18th birthday. At first I thought he was just being weird like he usually is. After all he was wearing a cow costume to work because my manager allowed it due to the fact that it was almost Halloween. OK maybe wearing a costume to work a day before Halloween isn't something to necessarily find fishy. But the thing that made him creepy was the fact that she had never told him when her birthday was prior to this. He just somehow knew. So when she asked him how he knew that he nervously paused for like 5-6 seconds before saying "it was posted in back roo...break room". I knew this was BS because my grocery store doesn't post any employees birthdays in the break room. I can tell she felt uncomfortable because some 35 yr old guy in a cow costume just randomly came up to her and gave her 18 hugs and he somehow knew it was her 18th birthday. She also had this "WTF" look on her face while he was doing this. They never even talk regularly because they work 2 completely different departments. This guy works in the backroom where we receive food shipments and she works as a bagger. I don't know, I could be wrong about him....maybe i missed something. What do you guys think?