Can electronics be damaged by undervolting it?
Damage by undervoltage is not as common as by overvoltage, but it is not unheard of. 

An example: a simple circuit that has a power mosfet driving a motor. The intention is that the mosfet is either completely on or completely off. In both cases the power dissipated by the mosfet is very low: 


when it is on the power is low because the o-fully-on resistance of the mosfet is very low, hence the voltage across it is also very low, so the power (V*I) is low. 
when it is off the full voltage of the power is across the mosfet, but the current is almost zero, hence the power is almost zero too.


A mosfet needs a certain voltage at its gate to turn fully on. 8V is a typical value. A simple driver circuit could get this voltage directly from the power that also feeds the motor. When this voltage is too low to turn the mosfet fully on a dangerous situation (from the point of view of the moseft) can arise: when it is half-on, both the current through it and the voltage across it can be substantial, resulting in a dissipation that can kill it. Death by undervoltage.

Note that I started by assuming a simple circuit. In practice a serious circuit like this would have an undervoltage protection.