Need Help : Busted Pedal (Causes????)

[vvictourette]

I just started playing bass about 3 months ago
I used to play rythm guitar so most of my stuff here are for guitars
2 amps and a few effects i havent sold already.

I recently bought a Bass overdrive
and I had my little brother set up the stuff.
well. he plugged the guitar to the wrong side of the pedal and POP! went my overdrive. and then i found out that the amp was busted too. good thing its the cheap one.
I'm not really sure , but my little brother told me smoke came out of the port and it smelled like bubblegum. and im wondering if thats the end of my overdrive. well. I dont want to commit the same mistake again and im just wondering what caused that.

is it my amplifier?
is it the misplugged plug?
is it the adaptor?

please help me.
thanks in advance