I had a blaster named Nuclear winter (rad/ice). His origin was that he was a reactor tech that just happened to be working when the Rikti were going after the reactor core and the heroes were hitting it with coolant.... He managed to stumble right between core and coolant...
MAN I loved my Rad/Ice blaster! Colored the rad bubbles to look like balls of snow. I'd run stealthed right into a group, drop an ice patch, then irradiate/neutron bomb until they're all dead. Just keep using Freezing Touch on the boss until all the luits and minions die from neutron bomb and irradiate, and then between Chilling Embrace, Ice Patch, Cosmic Burst, and Freezing Touch, you pretty much can stand one on one with anyone who isn't an AV. With the Achilles heal proc in both irradiate and Cosmic Burst his resistance is already way down, and with Chilling embrace slowing him, and ice patch and a Ragnarok and some damage procs in irradiate he's toast.
Johny Freeze. Best blaster ever.
:-)