Rainbow Core

“''Hello there gorgeous! Might I say you are looking as beautiful as a... rainbow?''” - Rainbow Core

Rainbow Core, voiced by Harry Callaghan, is an easter egg character that can be seen midway through the game. He has a single line of dialogue where he flirts briefly with Mel before leaving on his management rail. After he leaves, Virgil seems flustered by his presence, asking Mel if she “(got) that core’s serial number”.

Trivia

 * Rainbow Core’s voice actor, Harry Callaghan, also voices AEGIS, the antagonist of the game, and Cave Johnson.
 * Callaghan is also the creator of the popular Portal fan video series, Meet the Cores . Rainbow Core appears at the end of Meet the Cores 2 as a 'next on Meet the Cores' segment, but does not appear in Meet the Cores 3.
 * The Rainbow Core is one of two characters with only a single line, the other is Caroline.