Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_21 (plyff VARCHAR, opponent VARCHAR)
### Question:
What is the Plyff team that plays the Billings Outlaws?
### Answer:
SELECT plyff FROM table_name_21 WHERE opponent = "billings outlaws"