Supergirl met the heroes of "DC's Legends of Tomorrow" during The CW's four-night "Invasion!" crossover, but she never got to step foot inside their massive time-traveling ship. But according to Executive Producer Marc Guggenheim, it wasn't for a lack of trying.

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"There was a Supergirl moment on the Waverider that I really wanted to get in there," Guggenheim told Entertainment Weekly. "I’m not going to tell you what it is, because we may do it next year, but Supergirl never ended up on the Waverider, so we couldn’t do the moment."

Let the speculation begin as to what could possibly happen once Kara enters the Waverider. Could Guggenheim be referring to a comic book Easter egg involving Supergirl and time travel? Maybe the Waverider's navigator, Gideon, and Supergirl exchange some witty conversation. It is also hard to tell if the moment was meant to have major ramifications for Supergirl, or if it's of the less-serious variety.

Either way, with the option open for future crossovers involving "Supergirl," "The Flash," "Arrow" and "DC's Legends of Tomorrow," we're sure to find out the answers to those questions.

Starring Melissa Benoist, “Supergirl” airs Mondays at 8 p.m. ET/PT on The CW.