"Que te/le parta un rayo" = Get split by a lightening*

Informal and not very rude to say go to hell. There are many other expressions to imply the same, but I guarantee they are much more rude and impolite. I'll leave you with this one ;)

"¿Me hace esperar media hora para nada? Que le parta un rayo"
"¿Qué dices? No lo dirás en serio... Anda y que te parta un rayo"
"Sinceramente... ¡que le parta un rayo!"
"Que me parta un rayo si estoy mintiendo" (typical expression to show and prove your honesty)