I missed every opportunity to document this prop mushroom’s build, so you’ll have to just do the whole “theatre of the mind” business as I describe the process.

The southwest or desert miracle mushroom enjoys dry but shaded spots. Look for them near other vegetation.

I produced the cap separately from the stalk.

For the mushroom cap I first cut a home trash bag into 3″ strips, then laid laid them inside large (18″ diameter) chip bowl as shown below:
By lining the bowl with strips of plastic rather than larger sheets, the plastic better matched the form of the bowl. I then mixed and poured some FlexFoam-iT!® V expanding foam from Smooth-On into the bowl. I used a GLOVED hand to evenly spread the foam.

I waited until the foam started expanding (which was my cue that the foam touching the plastic strips was tacky and becoming solid) then I picked up the bowl and tipped the bowl in a circular rolling motion to evenly distribute the foam.

A sweet-variety desert miraculo nearing maturity. Now outgrowing the surrounding plants from which it leeched moisture and nutrients.

While the polyurethane foam mush-cap cured I ran down to the wood shop and, using the jigsaw, cut the following “kit” for the stalk structure out of 1/4″ plywood.

As you can see, they assemble into a locking structure as shown below:

Note: Add mild asymmetry as pleases the eye.

I then stuffed the void-quadrants with tissue paper, then wrapped with clear tape. I painted to match the pale yellow complexion of the foam.

Now we're cookin' with gas! Although toxicologists agree the milagro poses neurological harm to infants and the elderly if ingested raw, when properly prepared anyone may enjoy the this fungal treat. Baking whole (as pictured above) allows harmful enzymes to metabolize into simple sugars.