Complex sentence: As the Invaders all get robots that obey them, called S.I.R units, Zim gets a malfunctioning one, called G.I.R. G.I.R is obviously an idiot, but the Tallest cover this up, and send Zim off.
Split into simpler sentences: As the Invaders all get robots that obey them, called SIR units, Zim gets a malfunctioning one, called GIR. GIR is obviously an idiot, but the Tallest cover this up, and send Zim off.