And in the flashback in Jurassic Bark, there is an additional shadow, Fry. It wouldn't be until the Infosphere episode when we see that Fry traveled back to prevent Nibbler from freezing him, but ultimately decided not to.
The continuity in this show is incredible. One of the few cartoons of the time that had a running, consistent universe that frequently references itself.
~~B~~ Nibblers shadow, the delta brain wave, and bender fossilizing seymour being some of the better ones.
My mistake - it was explained 39 episodes later. And I can't modify post titles... crap...
The first Episode of Futurama is frequently referenced, so every detail was likely painstaking.
Your link mentions "The Why of Fry", but they also revisit the first episode in "Anthology of Interest I" and "Bender's Big Score".
I still want to know when my tv will be high def enough to see Amy’s obscene tattoo.
I heard the shadow was added in later DVD releas and was not present in the original airing
edit: according to posters belowe me, the shadow was in the original and rumors of it being added later are inaccurate.
Matt judge and mike groening are time traveling gods