I would choose the Bubbler Lvl3 from Cave Story. That way I have an army of Bubbles of Doom at my command. Either that or the Jetpack v2.
I would have a Master Ball...
Wait for it...
INSIDE!!! *evil laugh*
If there's already something inside what's the point of the masterball?
JUST FOR SHOW! GOT A PROBLEM WITH THAT?
I BELIEVE THAT HETALIA SHOULD BE A RELIGION! WHO'S WITH ME?
*cricket noises* What?
...I understand... *sits in corner, eating pasta*