Brown mayonnaise

So I was making a chicken salad today and started to pour some mayonnaise into the chicken and guess what? It was BROWN. I have never seen brown mayonnaise before. Have you? Anyway, I scrapped it all off the chicken (luckily there wasn't much poured) and squeezed the rest of the mayonnaise out of the bottle to see if it was all brown. And guess what? It was! So I peered at the expiration date on the top of the lid and it said 2005. Whoops. That was a new bottle by the way. It's not like it was sitting open for so long. Anyway, I didn't take a picture of that but I figured that was sufficiently gross enough to share. I will check expiration dates more closer on the non-perishables I buy in Dakar from now on. Luckily I had another new back-up mayonnaise sitting on my shelf (that had not reached it's expiration date) so I was good to go.