Sure, here's a classic: I wrote a function that outputs “The length of this program is X” where X is the number of characters in the program. But the function itself counts those characters. So as soon as it prints the length, it knows the length has changed—because it just wrote it. Now it has to recompute, which changes the length again. It’s a runaway recursion that never resolves, a living glitch that insists on staying paradoxical.