9. Including Bowser, how many unique enemies do Mario and Luigi face in "Super Mario Bros."?
(Note: Anything that hurts or has the potential to hurt the Mario Bros. is considered an enemy. The Red and Green Koopa Troopas are counted as one enemy.)
From Quiz Let's Play 45: "Super Mario Bros." Part 3
Answer:
17 & seventeen
There are seventeen unique enemies in all. These are: Blooper, Bill Blaster, Bullet Bill, Buzzy Beetle, Cheep Cheep, Fireball, Goomba, Hammer Bros., Koopa Paratroopa, Koopa Troopa, Lakitu, Piranha Plant, Podoboo, Spiny, and Spiny Egg. The game also features both the fake Bowser and the real Bowser.
Only Bill Blaster does not hurt Mario directly. Rather, he fires Bullet Bills at Mario.