Not much has been known about Wendy since the beginning of the series. Her first major role was when she was seen making out with Ted's dad in Brunch, which Barney captures an image of using his cellphone. Previously (although it is seen in The Platinum Rule), Wendy had sex with Barney and kept on flirting with him in the bar, but Barney finally had enough and broke up with her. Since then, Barney takes extra precaution when taking drinks from her in the crazy belief that she's trying to kill him (he even throws away Marshall's burger because he believes she might try and "get to" his friends).