Just keep punching,kicking,ground pounding and jump sliding until he falls into the Hot Boiling Stinky Lava.
fight the end dude
You have to beat world 6
Just beat 5th boss as Mini Mario.
secret exits
You have to beat Mummipokey (the boss of World 2) as mini Mario.
Beat world five's boss as mini Mario/Luigi.
You beat it.
You have to beat the Level 5 castle in mini Mario form.
if you mean new super Mario bros, then you beat world 6 castle when you are mini Mario.
die
beat world one.
beat world 6