Boss idea.
1) Maybe mario could magic a Mushroom into a monster that can jump and headslam the ground, drop spores up close that either simply damage koopa or if you want to program it, reverse the controls for about 10 seconds so up is duck, left is right ect. It could also charge at koopa. It's weakness lies in it's unstabability. If it charges into a wall or koopa shell slides it's legs it will flip over so koopa can danage it's stem since it's cap part just bounces koopa off.
Maybe you could make bosses out of the following items.
1) Soda can.
2) Microwave (it could close it's door, cook up fireballs and shoot em out).
3) Snooker ball (could form a centipede).
4) Duracell battery.
5) Chapstick.
6) Microphone.
7) Role of tape.
8) Tape Measure.
9) Screwdriver.
Eatemupstudios
More music ideas.
1) Music for sky night could be <a href="http://www.newgrounds.com/audio/listen/85870">http://www.newgrounds.com/audio/liste n/85870</a>
2) Music for plains day could be <a href="http://www.newgrounds.com/audio/listen/160300">http://www.newgrounds.com/audio/liste n/160300</a> or <a href="http://www.newgrounds.com/audio/listen/26139">http://www.newgrounds.com/audio/liste n/26139</a> (remix)
3) More music for yoshi mini boss could be <a href="http://www.newgrounds.com/audio/listen/98992">http://www.newgrounds.com/audio/liste n/98992</a>
4) Music for nighttime ice could be <a href="http://www.newgrounds.com/audio/listen/104902">http://www.newgrounds.com/audio/liste n/104902</a>
5) Map music at night could be <a href="http://www.newgrounds.com/audio/listen/114630">http://www.newgrounds.com/audio/liste n/114630</a>
Lambtaco
1) It's kinda short and very techno.
2) 1. I know this would get annoying fast. 2. I was planning on using this as battle music for scribble koopa at one point. Also annoying.
3) A little slow getting in and it's a remix. More specifically it's a little too intense for what Ineed.
4) I played the hell out of Blockside 2 so I can't hear this in anything else.
5) This is pretty neat. Seems a little heavy on bass, and I'm not sure if it fits right. But it's one of your best map music suggestions, probably the best.