*based from the words "telepathy" and "pathetic"
It is usually used as a punchline when someone tries to read another person's mind and fails to do so.
Teacher: Since you are all telepathetic, I will communicate the lesson to you all orally.
Psychic: I am telepathic and can read you mind, but only for a small fee.
(client pays small fee)
Client: so can you tell me my real name?
Client: so that makes you telepathetic!
Rebecca: What? Your mom is getting fatter? That's not deja vous.
Bree: Whatever. Your mom is fat too.
Rebecca: You're totally telepathetic!