Blood Vision

You touch a willing creature to grant it the ability to see in the heat signatures of any creature within range.. For the duration, that creature has a special darkvision out to a range of 120 feet. The sight of the creature is limited to only shapes giving off heat excluding plants and the undead. The creature has advantage against creatures with temperatures opposite to their surroundings with attacks and ability checks dealing with sight. 

If cast at 4th level or higher, the spell picks up heat signatures given off by the undead.