Low ECL undead?

[Kumori]

Hello playground. I'm wondering if you can help me out... I'm looking for a race or template that has as low an ECL as possible that changes type to Undead.
It can be from almost any official WotC source, just let me know where to find it.

Thanks in advance!

[hivedragon]

necropolitan (libris mortis)

[Kumori]

necropolitan (libris mortis)

ECL+0... I like that. Thanks.