First: ooze or undead with oozlike qualities?
Do we want true weapon immunity or DR more like a normal ooze? As for the magic stuff, I'd say we more or less cut & paste from a golem, using dispel magic and anti-magic field.Because of its liquid state, lich’s blood is immune to all weapon-based attacks. Thanks to its magic-draining nature, all spells cast on it are absorbed harmlessly. The only way to kill a lich’s blood is to use nonmagical acid, fire, or the deprivation of magic. A dispel magic spell cast on lich’s blood causes 1d6 hp damage per level of the caster; an anti-magic shell cast on one destroys the creature immediately.