Proc-based item brands

Here are some suggestions for beneifical and hindering item brands I've been thinking of implementing, based upon procs. There are three types of procs - those that have a chance to occur when an attack is made (i.e. offensive), those that have a chance to occur every turn, and those that have a chance to occur when a creature gets attacked (i.e. defensive). Some (e.g. torment) are more powerful than others - I haven't worked out competitive power rankings yet but I would like the slightly less powerful effects to be more common than the more powerful ones.

I envisage these brands would be placed upon magical items in a similar fashion to other brands, although their names would take precedence in item name construction.

Suggestions for more, and their frequency would be more than welcome.

Offensive beneficial effects:

1. transfer 10% of hp from target to attacker [vampiric]
2. inflicts 50% extra damage [vorpal]
3. reduces maximum hp of target by 25% [draining]
4. teleports target to random place on level [telekinetic]
5. teleports target away permanently [banishment]
6. turns a normal hit into a critical [slaying]
7. knocks target back a number of squares to the nearest wall [thundering]
8. turns a single attack into two or more attacks [quick]
9. chains the damage to any adjacent targets [chaining]
   

Offensive hindering effects:

1. drains target of 10% of hp and returns it to the attacker [withering]
2. turns an attack into a miss [clumsy]
3. makes the target trip and fall, thus losing the current action [stumbling]
4. teleports target randomly around the level [blinking]
5. injures target for half hp [tormenting]
6. randomly makes target drop an item carried in inventory [itching]
7. randomly eats a carried ration of food [consuming]

Defensive benficial effects:

1. absorbs the blow entirely [shielding]
2. heals the target for the damage the hit would otherwise have caused [restoring]
3. makes target's evasion temporarily higher and forces the attacker to reroll the triggering attack against the new evasion [displacing]
4. knocks attacker back one square (if possible) [rebound]

Defensive hindering effects:

1. freezes the target in place for a turn [rooting]
2. terrifies the target, cutting the target's evasion rating to 0 temporarily and allows a reroll of the triggering attack [terrifying]
3. allows the attack to proceed at full damage, ignoring armour [piercing]
4. teleports a nearby but non-adjacent creature to a square adjacent to the target [attracting]

Now these effects are relatively easy to code, being all instanteous effects. But if you have any ideas for longer lasting effects, it would be good to read them as well.

A few of these procs also might make good scrolls as well.