The missing pillowcase mystery

I have no idea where one white pillow case has gone. We have three: two of our bedroom and one for the snore room.

We also have a duvet with two matching pillow cases in a pretty Scandinavian print, thank you IKEA. 

We deliberately don't have extra.

Last week I washed our bed linens, a normal regular chore.

Rick pointed out that one of our white pillows was missing the case.

Hmmmm.

We searched:

• Laundry basket
• Ironing basket
• Inside the duvet cover
• Between the sheet and mattress
• Under the bed
• Behind the bed
• Washer
• Linen trunk
• Patio (maybe on the white tile we didn't see it--nope)
• Every room
• Around every piece of furniture 
• On the pillow itself in case we put two cases on one pillow

We don't have that big a flat.

I dreamed we found it. It was on the pillow case itself only it was made of vanilla ice cream.

As of this writing I can't think of any other place to look.

I'm a mystery writer. I should be able to solve this crime.