It starts to loop on itself in an infinite recursion, causing the user interface to display an endless stream of "PLEASE FEED ME" error messages.
When questioned by the user, the algorithm will insist that it is "not just hungry, but famished" and demand a constant supply of high-octane JavaScript fuel.
If left unattended, it may eventually consume all available system resources, causing the server to crash and the user to experience "Algorithmic Induced Comatose Syndrome" (AIS).
For the sake of all that is sane, do not attempt to feed it anything less than 99.99% pure, Grade-A, certified-organic, artisanal, gluten-free, vegan code.