Pseudocolus fusiformis

Stinkhorn fungus, probably immature, growing in rotting wood.
Dwyer Road, Imbil, Queensland, Australia

When fully mature, many stinkhorn fungi species resemble penises and smell of rotting flesh, which attracts flies to disperse their spores.

If a brief internet search is to be believed, they are a smelly and unnatractive invader in some gardens...