messy monkey
a difficult or complicated situation. Something that is going to take a bit of work to resolve. The origin of this phrase is derived from urban monkeys in Southeast Asia who you definitely don't want to have anywhere near your house, as they have been known to break and enter, and trash the premises in no time flat looking for anything edible.
In referring to the BP oil spill in the Gulf, former President George Bush might have comments by saying , "You see here, what we got in the Gulf is whatcha call a messy monkey. It's gonna take a lot of effort to clean it up and it's gonna take some time to get that leak plugged.