You can bet everyone over at Warner Bros. is having a Maalox moment right now. The studio’s dark, downer of a superhero film “Watchmen” is set to open at midnight tonight, and the big question is, can it be profitable? This is a $120-million film with no sequel potential, little merchandising value (Look, kids! It’s a toy Rorschach’s cleaver!), and a two-hour-forty-five-minute running time that will limit the number of showings that can be squeezed into a day.

Nonetheless, the massive marketing campaign and fanboy enthusiasm should put many butts in seats — costumed or otherwise. Box office guru Steve Mason’s predictions after the jump. Mason writes that the low-ball prediction for “Watchmen” around Hollywood is $55 million, with many feeling $75 million is “in the bag.” Mason is a bit more conservative.

FINAL PREDICTION FOR MARCH 6-8:

1. Watchmen (Warner Bros) – $63M

2. Tyler Perry’s Madea Goes to Jail (Lionsgate) – $11.5M

3. Slumdog Millionaire (Fox Searchlight) – $9M

4. Taken (Fox) – $7M

5. Jonas Brothers: The 3D Concert Experience (Disney) – $6.75M

6. He’s Just Not That Into You (Warner Bros) – $4.2M

7. Paul Blart: Mall Cop (Sony) – $3.9M

8. Coraline (Focus) – $3.2M

9. Confessions of a Shopaholic (Diney) – $3.1M

10. Street Fighter: The Legend of Chun-Li (Fox) – $2.1M