Ichigo's bankai: that trick where he, like, makes his guitar talk. you know?
Renji's bankai: POWER STANCE
Mayuri's bankai: a big floating pig drops down from the sky.
Byakuya's bankai: a totally bitchin lightshow.
Zaraki's bankai? zaraki doesn't NEED a bankai, he just fucking SHREDS his guitar.
Aizen's bankai: he lip syncs, the faggot.