Family Matters: Season 3, Episode 22
The Urkel Who Came to Dinner (3 Apr. 1992)
Urkel is invited to stay with the Winslows when the nerd's parents go out of town ... and quickly causes plenty of chaos. He drives Laura's study partner away, convinces Richie to get into a fight with a preschool bully, and accidentally vacuums up Lt. Murtaugh's fish that Carl was baby-sitting.