Why Trill Suddenly Had Spots In Star Trek: Deep Space Nine
By WITNEY SEIBOLD
On "Star Trek," the Trill species have worm-like symbionts that are surgically implanted in their stomachs, and they can live through dozens of hosts and take over their personalities.
Odan (Frank Luz), a man with inverted v-shaped forehead ridges and an extended septum, was the first of the Trill species introduced on “Star Trek: The Next Generation.”
Later, "DS9" featured a Trill named Jadzia Dax (Terry Farrell), who was given the Dax symbiote after it spent many decades inside the body of a party-loving old man named Curzon.
Dax doesn't have the same forehead ridges that Odan did. It seems that the makers of "Deep Space Nine," after trying out similar ridges on Farrell, elected to do something less obtrusive.
According to the book "Star Trek: The Next Generation 365," Dax's makeup artists modeled her new "spots" after Famke Janssen's in another "TNG" episode.
While the series already had several alien characters needing hours-long makeup jobs, the studio just didn't want an attractive actor like Farrell to have a weird forehead.