Those Guys and Master A. open up the level, with Teacher A. spawning a few seconds later. Teacher A. and Master A. will spawn at a steady rate throughout the level. Otta-smack-u begins to appear after some time, however Master and Teacher stop spawning. When you hit the base, be prepared, as THE SLOTH, 3 Shadow Boxer K's, Otta-smack-u and Teacher A. all come out. THE SLOTH produces a boss shockwave.
Oh, boy. Prepare yourself, as all hell breaks loose after you hit the base. Master and Teacher A. are very annoying early on, but aren't too hard to beat after a bit of stacking. THE SLOTH, however, is very annoying if you didn't bring any long range or multi hit cats.
I L U is a slang for "I love you"