Scoffing at Scousers

At what type of annual event might you hear the words ,"He's Behind You!!!" ?
Bernado Silva, "A Pantomime"
Marcus Rashford, "A Pantomime"
Mason Mount, "A Pantomime"
Harry Kane, "A Pantomime"
Gabriel Jesus, "A Pantomime"
Trent "The Champions League Final"
Bernado Silva, "A Pantomime"
Marcus Rashford, "A Pantomime"
Mason Mount, "A Pantomime"
Harry Kane, "A Pantomime"
Gabriel Jesus, "A Pantomime"
Trent "The Champions League Final"