The act of taking a single (often minor) action or trait of a character within a work and exaggerating it more and more over time until it completely consumes the character. Most always, the trait/action becomes completely outlandish and it becomes their defining characteristic. Sitcoms and Sitcom characters are particularly susceptible to this, as are peripheral characters in shows with long runs. The trope is named for one of the examples in The Simpsons, Ned Flanders, who was originally just a considerate neighbor and attentive father, with his devout nature simply being that he willingly attended and paid attention in church, all to make him a contrast to Homer, before becoming obsessively religious to the point of being an utter jackass.

http://tvtropes.org/pmwiki/pmwiki.php/Main/Flanderization

tl;dr When Chip first appeared he was a somewhat unaware corny comedian. Now he's a full blown weirdo.

https://www.youtube.com/watch?v=DhZVfDIl1To