I never thought about it, but it makes perfect sense! Oscar the Grouch is a Timelord with a TARDIS!
(http://nodwick.humor.gamespy.com/ffn/strips/2011-05-24.jpg)
source: http://nodwick.humor.gamespy.com/ffn/index.php?date=2011-05-24 (http://nodwick.humor.gamespy.com/ffn/index.php?date=2011-05-24)
Ha, it's bigger on the inside.
Waaaaa!