looks like an ESC
if those three light blue wires go to one of your motors
and the small red white black wires go to the power board servo rail
and the big red and black wires go to the power distro board that is an ESC
should have been covered in black heat shrink, and possibly had a 20A sticker on it
Thanks Pyrate. Completely helpful, and totally correct from what the Internet is telling me. Electronic speed controller. 20 amp. Anything else I should know before I order one from my local hobby shop? Like would this (Flycolor 20 Amp Multi-rotor ESC 2~4S with BEC be a suitable replacement for the x8 esc?