Spells Without Number

I've been working on a swords & sorcery fantasy hack of Stars Without Number. Basically I'm going with three classes. The Warrior, Rogue (Expert), and Sorcerer (Psychic). The first two classes are essentially unchanged from how they appear in the book, but the changes to the Psychic requires a bit more work. I was inspired reading in the psionics chapter about how Psychics can "Torch" their minds to cast their powers without paying the power point cost. This is a system that could be ripped out and used in any retro clone RPG for spell casters. Heres my personal take on it below.

Brundle the Sorcerer over-channeled one too many times...

Over Channeling a Spell & Mana Burn

A desperate, foolish or just plain unskilled sorcerer may decide to cast a spell when he no longer has

any mana points (or spell slots) left to do so. This feat of sorcery is accomplished by over channeling more eldritch energy than the sorcerer is capable of handling and suffering a mana burn.

Any level of spell can be over channeled this way but for each spell cast in this manner the sorcerer must roll a d10 and consult the Mana Burn Effects Table. Regardless of the roll over channeling a spell is a painful experience for the caster and will cause the sorcerer's body temperature to dramatically increase. Skin will turn red or blister and be hot to the touch. The air will crackle with a tangible eldritch energy that can be felt by those standing nearby and the smell of burnt hair and cooking meat will create a horrific stench that will suffuse the air and take days to dissipate.

Sorcerer's whose Wisdom or Constitution scores that drop to 3 or less become NPC characters under the Game Masters control. A sorcerer with a Wisdom score of 3 has gone insane and will be under the influence of some cosmic or infernal entity or quest. A sorcerer with a Constitution score of 3 has become so suffused with eldritch energy that they are no longer human. They have become an infernal, cosmic, unique undead monstrosity hell bent on world domination or some other maniacal scheme. 

Mana Burn Effects Table

Roll 1d10	Effect
1	Permanently lose 1 point of Con and Wis
2-5	Permanently lose 1 point of Constitution
6-9	Permanently lose 1 point of Wisdom
10	No Permanent Damage