Sense mob aggro by X

[Stufoo]

You could use it when trying to stay hidden from the undead!

That's not what it does.

Scent is a method of pursuit, not detection. Deodorize was used to drop aggro after sleeping and/or gaining distance, as the monster would follow your scent after it woke up, or to find where you went. Alongside deodorize, you could drop scent trails without it by crossing a body of water, and rain and double-snow weathers remove scent in the area as well.

It did not remove blood aggro. This was a common misconception in XI.