Frank Costanza has become one of TV's most iconic characters and that's mostly due to the late Jerry Stiller's performance. Originally played by a different actor, magic was made when Seinfeld producers decided to recast and George's short-tempered and abrasive father was born.
Frank took part in many great Seinfeld episodes and he, along with Estelle Harris as George's mother, helped make the show comedically richer. Frank had several great storylines, especially the ones where he schemed with Kramer, but there are many episodes in which Frank's brief appearance still produced a memorable moment.
The Doorman - S6E17 - 8.2
'The Doorman' finds Frank living with George following he and Estelle's separation. After George and Kramer witness Frank exposing his large chest, Kramer convinces Frank to partner on a bra for men, "The Bro" (or "Manssiere" as Frank calls it). They take the idea to Frank's friend in the bra business, Sid Farkus, however, the pitch falls apart when Sid expresses interest in Estelle.
After George loses the couch Frank was sleeping on, Frank shares a bed with George and this scene produced one of Seinfeld's funniest moments. Frank and George are in bed together, and Frank offers him a bowl of wheat grain, asking George, "Kasha?"
The Handicap Spot - S4E22 - 8.3
When originally aired, actor John Randolph played Frank Costanza, however, soon afterward Seinfeld producers decided to go a different route and replaced Randolph with Stiller. When the show went into syndication, Larry David decided to pull a "George Lucas" and reshoot all of Randolph's scenes with Stiller for continuity purposes. Both versions of "The Handicap Spot" are available so audiences can see two versions of Frank Costanza.
While Randolph portrays Frank as angry, Stiller portrays him as volatile. Audiences can notice the strong difference between the two takes on the character by the way Stiller more forcefully smacks George in the head, in the episode. Looking back, audiences should be very thankful for the switch because TV history was created.
The Cigar Store Indian - S5E10 - 8.4
George has moved back in with his parents but has the place to himself while his parents are out of town. While they're away, George not only invites a woman over he becomes intimate with, but while his pals are visiting, Elaine takes Frank's TV guide.
When George's parents return, not only are they aghast to find "a prophylactic wrapper" in their bed, but collector Frank is horrified his most recent TV Guide is missing. Frank's obsession with TV Guide is one of Seinfeld's first displays of Frank's quirky traits, with him remarking, "Am I just supposed to turn it on and wander aimlessly around the dial?"
The Raincoats - S5E18&19 - 8.5
Jerry discovers his parents hate the Costanzas after they avoid accepting a dinner invitation to their home. George also has decided to sell his father's used clothes, unfortunately, they have moths, which thwarts Kramer and Morty's plan to sell raincoats.
A few classic Frank Costanza moments in "The Raincoats" include him spontaneously wanting to move after George mentions their house might have mice, declaring, "I will not tolerate infestation!" When Kramer thinks he sees one, he and Frank race to the back room and struggles to squeeze through the doorway at the same time.
The Shower Head - S7E16 - 8.5
Morty and Helen Seinfeld's move to a new Florida retirement community prompt the Costanzas to consider the same, which irks the Seinfelds, so in response, the Costanzas decide to move to the same community out of spite. However, George's glee over his new buffer zone is short-lived when his parents decide not to move.
The animosity between the Costanzas and the Seinfelds is at a hilarious fever pitch in this episode, and features one of the funniest threats in TV history when Frank calls up Morty and says, "This is Frank Costanza, you think you can keep us out of Florida? We're moving in lock, stock, and barrel. We're gonna be in the pool, we're gonna be in the clubhouse, we're gonna be all over that shuffleboard court, and I dare you to keep me out!"
The Fusilli Jerry - S6E21 - 8.7
Frank becomes enraged after he finds out Kramer "stopped-short" with Estelle and seeks him out for retribution. Unfortunately, they end up restarting their argument over the bra for men's name (Bro or Manssiere), and, in the process, Frank falls on a figure of Jerry, made from fusilli pasta.
According to the DVD commentary, when filming Frank's scream upon falling on the fusilli Jerry, Julia Louis Dreyfus had to dig her fingernails into her palm to prevent her from breaking out in laughter.
The Strike - S9E10 - 8.8
Kramer gets excited when he discovers that Frank invented his own holiday, Festivus. During Festivus dinner, Frank introduces the "airing of grievances" where he begins to berate George's boss Kruger, saying "You couldn't smooth a silk sheet if you had a hot date with a babe... I lost my train of thought."
However, the best moment might be when Frank tells Kramer the inspiration for Festivus came from a Christmas time fight with another man over a doll for George. Kramer remarks, "She must have been some kind of doll," to which Frank replies, "she was."
The Rye - S7E11 - 8.9
George's parents and Susan's parents finally meet for dinner and it doesn't go well. To make matters worse, George discovers that Frank took back the rye bread they brought to dinner because, according to him, they deliberately didn't put it out.
The dinner scene where the two families meet is particularly funny. Especially when Frank loudly inquires about the mating habits of poultry, and then flips out when Susan's father mentions a memorable scene from a movie Frank hasn't seen yet, exclaiming "I like to go in fresh!"
The Understudy - S6E24 - 8.9
Elaine suspects the manicurists at her nail salon are talking about her behind her back so she brings in the help of Korean-speaking Frank so he can tell her what they're saying. Frank discovers that his long-lost Korean love works at the salon and they briefly reunite.
It's in this episode viewers learn Frank thinks he has a foot odor problem as well as hearing him speak Korean when describing what his mistresses' father thought of him, "This guy... this guy's not my kinda guy."
The Serenity Now - S9E3 - 8.9
Frank starts his own computer selling business after watching a "provocative" movie on TV, "The Net with that girl from the bus." He enlists George's help along with George's nemesis Lloyd Braun and the two battle over who can sell the most computers, even though Lloyd actually isn't selling any.
Also, Frank has started saying "serenity now" to calm his explosive impulses, with little success, before George turns him on to a new phrase, "Hoochie mama." Estelle threatens to drive her car into the garage packed with Frank's computers, and the episode ends with Frank defiantly yelling "Hoochie Mama" over and over as Estelle drives in.