Sphinx

About
The Sphinx is a building unlocked at level 13. It has 3 stages to build. It costs 50 Zombucks.

Building
1st stage: 2nd stage: 3rd Stage:
 * 10 Amethyst
 * 30 Palm Logs
 * 15 Bat
 * 10 Aquamarine
 * 20 Board
 * 25 Green Marble

Treasure Loot
Similar to the Diamond Eye, presumably there are 4 total stages of rewards "Recipes and Rare Buffs", and that partial constructions will award stages based on how many were constructed. Due to the cost of building the Sphinx, further testing would be appreciated.