Tobi (current) vs. Madara (current)

[Lunir]

why was tobi afraid of madara when kabuto showed him the coffin?

Because one it proved he wasn't Madara and two it would hinder his fighting forces for the current war. Another thing to be noted is unlike current Tobi the tobi who originally saw the coffin didnt have rinnegan nor the resurrected Jinchuriki as hosts for his paths of pein.

 

[Hushabye]

Madara

 

[FloriGlori]

Tobi. No matter what Madara will do, it's all to no avail when Tobi is de-materialized.

 

[Urda]

Tobi FTW or "Draw."

 

[Peeboaiy]

Madara flat out

 

[Tartarus]

Tobi due to his space time jutsu