This is a quick and easy Minecraft plastic canvas project. This small monster spawner is the same size as most of the other blocks and will fit over mob heads. (I hope to have some mob head patterns up soon.)
If you haven’t yet, you’ll want to check out Getting Started in Minecraft Plastic Canvas for more tips.
The bottom is open. That is supposed to be zombie pigman, but he didn’t turn out as well as I would have liked.
Plastic Canvas Pattern and Instructions for Minecraft Small Monster Spawner:
1. Cut 5 squares 17 by 17 holes in 7-count black plastic canvas.
2. Using black yarn, whip stitch the 4 sides together then stitch the top.
3. Overcast the bottom in black yarn.
Image from Minecraft Wiki – Gamepedia