Dead Walking

As part of casting this spell, you place a copper piece under your tongue. The spell makes up to six willing creatures you can see within range invisible to undead for the duration. Anything a target is wearing or carrying is invisible as long as it is on the target's person. The spell ends for all targets if one target attacks or casts a spell.

Using a Higher-Level Spell Slot. Using a 3rd level spell slot changes the spell to last for 1 hour without requiring concentration. The duration increases further (without requiring concentration) by 1 hour for each slot level above 3rd.