Nancy Jean Cartwright (born October 25, 1957) is an American voice actress, film and television actress, and comedian.
 She is known for her long-running role as Bart Simpson on the animated television series "The Simpsons".
 Cartwright also voices other characters for the show, including Nelson Muntz, Ralph Wiggum, Todd Flanders, Kearney, and Database.
"I Love Lisa" is the fifteenth episode of "The Simpsons"<nowiki>'</nowiki> fourth season.
 It originally aired on the Fox network in the United States on February 11, 1993.
 In the episode, Lisa gives Ralph Wiggum a Valentine's Day card when she sees that he has not received any.
 Ralph reads too much into Lisa's gesture and, much to Lisa's dismay, relentlessly pursues her with affection.
 Lisa snaps at Ralph and angrily tells him they are not together and that she never liked him.
 Heartbroken, Ralph channels his feelings into his performance as George Washington in the school's President's Day pageant.
 After a thunderous applause from the audience, he is able to accept Lisa as just a friend.
"Chief of Hearts" is the eighteenth episode of "The Simpsons"<nowiki>'</nowiki> twenty-first season.
 It originally aired on the Fox network in the United States on April 18, 2010.
 In this episode, Homer and Chief Wiggum become friends after Homer shares a sandwich with Wiggum during his community service sentence.
 Meanwhile, Bart becomes addicted to a Japanese kids' game called Battle Ball, but Marge and Principal Skinner believe that Bart is dealing drugs.
 It is also the first episode in which Lisa Simpson does not deliver any dialogue.
Bart the Bear 2, also called Bart the Bear II, Bart 2, Bart II, or Little Bart (born January 20, 2000) is a male interior Alaskan brown bear actor who has appeared in several Hollywood films and television series, including "An Unfinished Life", "Into the Wild", "We Bought a Zoo", and "Game of Thrones".
 His trainers are Doug Seus and Lynne Seus of Wasatch Rocky Mountain Wildlife, Inc., in Heber City, Utah.
 Bart 2 was named after the earlier Seus-trained bear actor Bart the Bear, although the two bears are not related.
Chief Clarence "Clancy" Wiggum is a fictional character from the animated television series "The Simpsons", voiced by Hank Azaria.
 He is the chief of police in the show's setting of Springfield.
 He is the father of Ralph Wiggum and the husband of Sarah Wiggum.
Ralph Wiggum is a recurring character on the animated series "The Simpsons", voiced by Nancy Cartwright.
 The son of Police Chief Wiggum and a classmate of Lisa Simpson, Ralph is best known as the show's resident oddball, and is noted for his non sequiturs and erratic behavior.
 His lines range from nonsensical, or bizarre interpretations of a current event, to surprisingly profound statements that go over people's heads; and his behavior varies between blissfully unaware, to dim-witted, to awkwardly spontaneous, even occasionally straightforward.
 The very nature of the character has undergone seemingly differing interpretations over the years and within various media.
"This Little Wiggy" is the eighteenth episode of "The Simpsons"<nowiki>'</nowiki> ninth season.
 It originally aired on the Fox network in the United States on March 22, 1998.
 It was written by Dan Greaney and directed by Neil Affleck.
 The episode sees Ralph Wiggum becoming friends with Bart.
 Phil Hartman guest stars as recurring character Troy McClure.
"Ralph Wiggum" is the seventh track of The Bloodhound Gang's 2005 album "Hefty Fine".
"Exit Through the Kwik-E-Mart" is the fifteenth episode of the twenty-third season of the American animated television sitcom "The Simpsons".
 It originally aired on the Fox network in the United States on March 4, 2012.
 In the episode, Bart is punished by Homer after letting a rabbit loose in the house.
 He gets revenge on his father by spray-painting images of him with the word "dope" all over Springfield.
 Street artist Shepard Fairey encounters Bart one night and offers him a gallery show of Bart's artworks.
 However, Chief Wiggum suddenly appears during the show and arrests Bart for covering the town in graffiti.
 It turns out that Fairey is an undercover officer working for Wiggum.
"Bart to the Future" is the seventeenth episode of the eleventh season of the American animated television sitcom "The Simpsons".
 It originally aired on the Fox network in the United States on March 19, 2000.
 In the episode, after their picnic in the park is cut short due to a mosquito infestation, the Simpsons stop by at an Indian casino.
 There, Bart is prevented from entering because of his age.
 He manages to sneak in but is caught by the guards and sent to the casino manager's office.
 The Native American manager shows Bart a vision of his future as a washed-up, wannabe rock musician living with Ralph Wiggum, while Lisa has become the President of the United States and tries to get the country out of financial trouble.
 "Bart to the Future" was the second episode of "The Simpsons" after "Lisa's Wedding" to be set in the future.

Question: how is Bart to the Future and Ralph Wiggum related?
Answer: animated