The mayonnaise joke

So I was just checking out the Pedernales Poo Poo for news on Willie Nelson's condition, and came across this joke Keith Richards told:

This walrus had his car break down so he took it into the shop to be fixed and walked across the street to get a bite to eat while he waited. After a few minutes the mechanic walked in and said to the walrus, "Looks like you just blew a seal!" The walrus wiped his mouth and replied, "No man, that's just a little mayonnaise."