This was an actual incident at LepreCon 30 during Michael Stackpole's panel on the Star Wars books, though slightly embroidered for the sake of scansion (which still needs a bit of a tweak here and there), rhyme, and closure. Scribbled out as instafilk at the filksing later when I was short on material to sing. Polished up a bit.
Vader left his cellphone in the con room
Set aside for all the Star Wars stuff
He left it there through the panel later
Finding space at cons like this is rough
Vader left behind his bloody cellphone
While Stackpole held forth on writing craft
If Vader hadn't had his big black helm off
We would have wet ourselves before we laughed.
His phone had polyphonic speakers
that jingled out his merry ringing tone
The panel conversation halted
John Williams march song chilled us to the bone
Vader stomped in in a hurry
Knocking cups and papers to the floor
When the call got grabbed by voicemail
Vader glared and swished out through the door.
Michael dragged us back upon the topic
And we thought the incident was through
He started going on to world-building when
Vader's cellphone rang with phonecall number two.
This time our friendly Sith Lord had his saber
And made to slice and dice the bloody phone
But alas --- the costume was all plastic
So Vader checked his voicemail ... then phoned home.