Ghost Employee

So today I came into the office to work a bit. I rolled in around 10am, ready to meet my co-worker to learn how to do what is going to prove to be The Most Annoying Work Ever. As I pulled into the parking lot, I saw that the company's ex-president/current C-something-O (CEO? CFO? COO?) was chatting with someone. I walked toward them donning my hoodie sweatshirt and sipping my coffee, when they saw me. Ex-pres looked surprised, and said something along the lines of, "Oh, you still work here?"
I tried not to chuckle, but am amused that one of the company's big kahunas didn't know I was still employed! Granted, I am only working part-time from home, but still! Makes me wonder what I can pull off without the company knowing!