Rule variant idea for D&D

Here's an idea I had for a rule variant in D&D:

Instead of weapons being enchantable, the weapons enchant themselves as they slaughter consecutively more creatures. For every creature a weapon kills, add that creature's character level to a stat called "LOCK" - Level of Creature Killed. Simple, eh? The weapon must be the one inflicting the final damage that claims the life of the creature.

When a weapon reaches 100 LOCK (should happen between 7th and 8th level), and again every 100 LOCK after that, it receives a small enhancement bonus.

1st LOCK: +1 damage of type (ie, +1 fire, +1 ice, +1 sonic, +1 piercing, or +1 slashing), or +1 attack.

2nd LOCK: +2 damage of type or +2 attack.

3rd LOCK: +3 damage of type, +3 attack, or etherealness (stacks with 1st 2 LOCKS).

4th LOCK: +4 dmg or atk, or cast 1st - 3rd level wizard or cleric spell once per day.

and so forth Sphere: Related Content