Things you REALLY don't want a timetraveller to say

[Draz74]

"Whatever you do, DON'T EAT A SANDWICH. EVER!"

"OK, get in your car and start the engine ... I have to be there to see what happens when the President walks under a ladder tomorrow."

"It's too bad you guys don't know about the planetary convergence ... no, not those planets; nothing happens when Mercury, Venus, Mars, Jupiter, Saturn, and Neptune line up. The interesting stuff is the forbidden planets."

[Segev]

"Wait, you mean Revenge of the Sith came out last decade? It's not a thinly veiled commentary on--er, never mind."

[dps]

Gee, this used to be a nice place before--uhm, never mind.

[Altair_the_Vexed]

"You are your father."

EDIT: Now I'm thinking about a Dr Who / Star Wars cross-over in which Luke is Vader!

[Thomas Hunter]

"You are your father."

EDIT: Now I'm thinking about a Dr Who / Star Wars cross-over in which Luke is Vader!

Holy crap, the Dagobah cave just got THAT much more terrifying.

Two time travelers show up at the same time. The non-plot-central one attempts to kill a PC, the other protects him, and after winning, says "You know you aren't allowed to screw with major historical characters! Yes, even if they're [insert PC last name]!" Bonus points if any of the players have read wikihistory.

[Jay R]

"You still have both hands and both eyes? Oh, good - I got here in time to watch it."

[Deophaun]

"Give him the keys. Save the girl."

"Good, I made it in time for the Bee Gees revival!"

[Segev]

"Oh, man, the 2014 World Series? I LOVE watching 9th-inning come-from-behind victories!"

[Jakodee]

Have a huge explosion centered around a tall haunt man in a futuristic suit who slowly walks up to a PC. Then he starts laughing hysterically and leaves.

[Jakodee]

"Wait a second... Why are you a guy?

[Codex]

"So that's what you look like without tentacles!"

"You look just like your picture in the family album."

"Oh no! A Temporal Pair-o-Socks!"

[Mrc.]

"Get down Mr. President!"