Sandy took the crying Seymour to the theater to see his father, and tell him that she's going to put a paternity suit on him. After the parents argue, Arthur, Sidney's friend, decides to look at Seymour, and see if he's really Sidney's kid. After getting a close look at him, he turns to Sidney, and says, "It's got your eyes, Sid."
Seymour later appeared, along with his mother, crawling on stage when his father was about to introduce Wynyard, the knife thrower. As he crawls up to him, and repeats the word, "Dadda," Sindey runs off stage quickly to get away from his ex-wife, his supposed son, the audience that was laughing at him, and to use the bathroom.
Soon, during Heidi's rampage, Seymour was trying to be dragged out of theater by Sandy, but, after she got her head shot off, he was left out into the open. Suddenly, Sidney's parental instincts hit him, and went to save his son, at the cost of getting his kneecaps shot.
Nowadays, Seymour is currently working in an orchard as a struggling horticulturist along with his father, who got full surgery on his kneecaps.