"These bugs cause time to go backward, which really screws things up."
"They must have picked up a bug-but what bugs cause such symptoms?"
In high numbers false chinch bugs can cause significant plant damage.
The millennium bug, on the other hand, might cause a big crash.
A bug in a file system can cause catastrophic data loss for millions of people.
Maybe a bug is causing the disease and somehow gets involved in all these symptoms.
Functional bugs cause programs to fail or to give erroneous results.
One major bug would cause the player's system files to uninstall when the game itself was removed.
More serious bugs may cause the program to crash or freeze.
The bug caused this method to enter an infinite loop when called on a specific input.