Infuse Decay

This spell functions as per imbue with spell ability, except it can only target corporeal undead creatures, and can only transfer touch spells. The number and level of spells the subject can be granted depends on the undead creature’s Hit Dice; even multiple castings of infuse decay can’t exceed this limit.

HD of Undead	Touch Spells Infused
5 or lower	One 1st-level spell
6-10	One or two 1st-level spells
11 or higher	One or two 1st-level spells and one 2nd-level spell

Once you cast infuse decay, you can’t prepare a new 4th-level spell to replace it (see imbue with spell ability for further details). The infused spell is automatically triggered the next time the undead creature makes a successful touch attack or attack with a natural weapon. An intelligent undead can choose not to trigger the spell on a hit. Only one infused spell can be triggered per attack. An intelligent undead can choose which spell to trigger if it has more than one infused spell. A nonintelligent undead triggers a random spell when it hits with a natural weapon. Only one spell can be triggered per round, regardless of the number of attacks the undead makes.