These small (2-3mm) grey/brown balls are the fruiting bodies of "wolf's milk" slime mold growing on a decaying <i>pinus radiata</i> log.  They started out orange (see other versions) but changed to this grey/brown colour a couple of days later, after rain.  The damage to the surface of the nearest ball is from me touching it. Wellington, New Zealand.
Tony Wills
CC BY 2.5
<span class="int-own-work" lang="en">Own work</span>