The Mecha Dragon is a boss in Mega Man 2.
To get to this boss, Mega Man must hop on the blocks and the Mecha Dragon will chase him and he will battle on the blocks.
The best ones is to use a bunch of Quick Boomerangs from Quick Man or Atomic Fire from Heat Man. He must save the Atomice fire for the Wily Machine.
In this mode, it's unlikely for Mega Man to use Atomic Fire as he must save it for Dr. Wily. He must keep attacking until it's dead.
Mega Man Power Fighting Series
Since, Bass will be the best fighter to beat Mecha Dragon, except he should keep hitting him with the Quick Boomerang. Or players could use Mega Man or Proto Man to finish him off.