Three vampires went into a bar and sat down. The barmaid came over to take their orders.
"And what would you, er, gentlemen like tonight?"
The first vampire said, "I'll have a mug of blood." The second vampire said, "I vill have a mug of blood, too." The third vampire shook his head at his companions and said, "I vill have a glass of plasma."
The barmaid wrote down each order, went to the bar and called to the bartender, "Two bloods and a blood light."