New
#21
The static charge that was on the controller most likely traveled to the USB port on the computer. From there, it should have been sent to ground via ESD protection circuits* and the ground connection on the APC battery backup. Your APC unit might have a light or some other indicator to tell you that it is happy with the ground that it has from the wall outlet.
*rated to handle 8kv to 15kv - depending on the vendor.
...which is too low - IMO :-(
8kv rating from NXP (PDF)
15kv rating from TI (PDF)
So, to answer your question: "Could the controller of fed electricity back into my motherboard and damaged it? " Yes, it could have; despite the ESD protections built-in.