It is a very sick eucalyptus tree. It is probably being attacked by one of several borer beetles we have in the southland. If you scrapped back at the start of the flow, you would find a small hole -- the tree is trying to purge the bug by bleeding sap. There is nothing that can be done once it reaches this stage except taking down the tree. Don't park near it -- the limb joints are a prime festation spot and we have had sizeable (ie car wrecking) limbs pop off in the wind and during sudden temperature changes.