Rose returns to Two and a Half Men during the eight season to stalk Charlie and possibly ruin his relationship with Michelle (Liz Vassey).
Added:

Two and a Half Men Season 8 Episode 7 Quotes

Michelle: You have a wonderful son.
Evelyn: Yes I do. But Charlie and Alan must never learn of him.

Michelle: You eat a lot of fish. Aren't you worried about mercury?
Charlie: Michelle, on the list of things I expect to kill me, mercury poisoning ranks well below liver failure, struck by lightning and heart attack during sex. Guess which one I'm rooting for?