I'd do someting similar to scorpion's spear move, but I'd use lighting chains, shock them, pull them over towards me, then uppercut them with my fist encased in blue flames. Then, for a finisher, rip their arm off, light it on fire and throw it at their heads at around 800 mph.
Maybe I could get a job as a fatality designer for the next Mortal Kombat! What a fun job that would be, as well as a demented one. If someone asks you what you do, you say "I get paid to think of the goriest most over the top ways to kill people."