Why is my spell not working?

[Moeboid]

I created the following spell and I can't figure out why is fails to kill a Steam Centurion:

Weakness to Magicka 50% for 1 second on touch
Drain Health 100 pts for 1 second on touch

A Steam Centurion apparently has 150 health, which is exactly how much the spell should do. I tested a similar spell on myself and it did the correct amount of damage, so I can't figure out why this one isn't working. Any ideas?

[Dagoth Ur]

There was a removed note on the wikipage about the Drain effect not being able to kill outright. Try setting your health to 150 or less and try the spell again to test (although it does sound a bit unlikely).

[Iaius Amaius Heron]

Sometimes the Weakness to Magicka doesn't last for one second.

I've found it usually works if you set it to 2 seconds, then back to 1 second on the slider.

If not, make sure to quicksave BEFORE you make the spell, and then use the placeatpc command on a creature whose exact HP you know (and has no resistances) so you can gauge the damage and see if it's resulting in what you're expecting.

Also, through extensive console testing (with GetHealth) I've noticed that spells don't do exactly the damage they say they do. They actually do maybe 95% to 99% of what it's said, meaning if you have a spell that does 200 damage, it seems to do 190 to 199 actual damage.

My guess is the enemy's Willpower has a small influence on how much damage it takes from spells, but I haven't tested this. Though it'd be easy...

Edit: experiment results are in. With the last statement, I meant to say, "I see no difference in damage from the spell by altering Willpower..."

[Moeboid]

Ok, did some testing and it looks like at some point it becomes necessary to do 1 extra point of damage. All of my spells below 100 have worked - that is, they have been capable of killing the creatures that they're supposed to - so perhaps an extra point of damage becomes necessary for any spell stronger than 100 points.

My character has 140 health and both of the following spells failed to kill me, leaving me with 1 health:

Weakness to Magicka 40% + Drain Health 100 pts
Drain Health 140 pts

However, when I increased the Weakness to Magicka to 41%, the spell was capable of killing me.