Stir in marshmallows until completely melted. Remove from heat.
Stir in cereal til well-coated. (*Iused 6 1/2 cups because I think they come out less dry.And they hold up better if they have to sit out for awhile). The original recipe called for 7 1/2, but what i used worked out really well!).
Press into a greased 13x9x2 pan with a buttered spatula. Cool.
In large mixing bowl, beat cookie dough and flour til well mixed.(*You do have to add the flour, otherwise that store-bought dough is really awful - very sticky!).
On a lightly-floured surface, roll dough into a 6 x 16 rectangle.
Cut into 16 small rectangles. 2 rows of 8. Each one being 3 x 2 .
You can trim tops (2 side)with a paring knife to resemble the top of a tombstone cutting an arch if desired.
Place each tombstone onto ugreased baking sheets 2 apart.
*Optional, along bottom edge (bottom 2 side)of each cookie, insert 2 toothpicks halfway into the dough. **If these will be for small children, I recommend not doing this. (My owm alternative directions to follow.).
Bake cookies at 350º for 8-10 minutes or until edges are golden brown.(*Mine took 13-14 minutes.)But mine were probably a little thicker than the original recipe. It had said to roll out and hand-cut each cookie with a paring knife around a waxed paper pattern - (Cutting them into rectangles from a large rectangle was MUCH easier! And made more sense to me.)Then just simply trim the tops to whatever shape/style you want.
Remove to wire racks to cool.
In large plastic ziploc bag, combine water and green food coloring.
Add coconut, seal bag shut, and shake to coat.
Toast coconut, set aside. (Optional.)I didn't, it was fine.
Using black gel, tint frosting gray. (*I used one whole small tube and it was barely gray, but ok.).
Frost cookies, decorate tombstones with more black gel. (*The black gel for writing didn't work for me! I had to scrape it off, refrost the ones I wrecked, and just used chocolate frosting instead for the writing part. That worked perfectly for me.).
Cut cereal bars into 3 x2 rectangles.
Spread with melted chocolate chips. (*I didn't do this, I used frosting instead.)BUT! See further instructions!
Insert cookies into rice crispy treats sticking the toothpicks down in to hold up the cookie.
Do this on the edge of one long side.
*If you aren't using toothpicks, pipe a thick bead of melted chocolate chips on wide edge and hold in place til set. Or do on waxed paper, which is how i ended up doing this, and lay them down with the cookie pressed against it so you don't have to hold it. Refrigerate til set.(30 minutes was all it took.) Remove from waxed paper carefully.
(*I then opted to use the rest of the chocolate frosting to frost the tops of the exposed rice crispy treats part. Pressed the pumpkin into the frosting, then sprinkled with coconut.).
Decorate with coconut for grass , and candy pumpkins.