I know exactly which sticker you saw - the one with lightning bolts dancing around inside the guy's chest. :) There's also one with a somewhat-anthropomorphic spark: http://www.keepgraysharborfishing.c.....ign-S-2250.gif

Reddy Kilowatt is also somehow related to this. https://en.wikipedia.org/wiki/Reddy_Kilowatt

I think my favorite warning graphic is the one of a guy getting caught in a tractor driveshaft: https://upload.wikimedia.org/wikipe.....g_label_01.JPG

That's amazing! XD