Peal and chop the garlic. Cut one avocado in half, reserve the side with the seed in it, add the flesh of the avocado, garlic and lemon juice to a blender and pulse until smooth, especially the garlic.
Add the flesh of the second avocado and cumin then pulse until well combined and at at your preferred texture.
Finely dice the tomato removing the wet internal seeds and flesh. Stir into the guacamole. Taste and adjust to taste, with salt, cumin and lemon juice.
Take the reserved guacamole half and carve in a skull face, cut all the way through to the seed to expose the stone.