Doctor Wahwee is the 100th enemy encountered in Boss Fights. Killing it unlocks Mega Lands and UUG, The Unmentionable. It is also a monster you battle in Adventure Mode, found in the Mega Lands as DOCTOR WAHWEE (BOSS).
|“|| At last, you've made it to the big bad himself. The mad doctor spits out some lispy villainous speech about his plans to dominate the universe with the traitor before moving towards some giant mech contraption. You graciously give him time to be safely hidden away in his mech instead of just ending the fight here and now.
...he's having some trouble using the step up to climb in. Poor guy.
Alright, he's safely in his giant death machine. FIGHT!