Today’s brain-melter: Every Insanely Mystifying Paradox in Physics. It’s all there, from the Greisen-Zatsepin-Kuzmin limit to quantum immortality to, of course, the tachyonic antitelephone.
A tachyonic antitelephone is a hypothetical device in theoretical physics that could be used to send signals into one’s own past. Albert Einstein in 1907 presented a thought experiment of how faster-than-light signals can lead to a paradox of causality, which was described by Einstein and Arnold Sommerfeld in 1910 as a means “to telegraph into the past”.
If you emerge with your brain intact, at the very least, you’ll have lost a couple of hours to the list.