Intrude-a-window

When intrud-a-window enters the battlefield, create a 1/1 flying thopter token creature. During your combat phase, create {x} 1/1 flying thopters where {x} is the number of token creatures on the battle field. Sacrifice all thopters created this way at the start of the post combat main-phase.
We have an intruder!
How did he get in? Intrud-a-window!?...Buh-bye!