I can see this being the plot of some wacky 90s era show.

Little girl is walking down the street with mom, and sees a guy dressed up in a unicorn suit.

Says "hes mine" and the guy gets "comically arrested"

Fast forward to court, and the guy has no lawyer, but tries to defend himself with the ol "it's just a suit!" And takes off his helmet. He still looses the case, and is ordered to live with the family and can never take off his costume.

Family turns out to be rich and lives on a mansion, and now this guy goes around acting like a really miserable and disgruntled "unicorn"......but occasionally gives out great life advice to the members of the family.

All of this happens in the intro, to some upbeat music.