Early episode, "Mind War", where a character becomes, to steal from
Scott Adams, "a godlike being of pure energy". A transition executed by
a bunch of races a billion years before and by the human race a million
years hence. Telepathy and telekinesis are involved, though, with JMS
being coyly evasive as to whether they are wholly reducible to
technology.
The million-year-hence scene might be good, for surprise.
Oh, and said character zaps another character who slowly becomes
considerably more powerful. Still psionics, though.
-xx- GCU I'm Color Blind; I Only See Grey X-)
"However, one should also point out that lab mice are _very_ _very_
stupid, and are incaple of survival outside of the laboratory
environment where their biggest day to day problem is rediscovering that
today the food is on the left side of the cage."