There are loads tons of flaws, traits, and feats that grant "bad luck" using them all is painful and hilarious. Here is a build based off of the pathfinder(3.5) gnome jinx and internet flaws/feats that sounded too good to pass up. There are some holes, because I passed the character onto another, but you can rebuild and make it stronger.
First ask if your DM will allow action or hero points; racial traits; arcane casters; and regular traits: If YES prepare the character bomb shelter!
Second be a human and take the racial traits: "raised by other race" the race is Gnome; "Gnome jinx"
--> a Gnome jinx is almost a hexblade, but the bad luck comes from within.
3rd) Now add 8 flaws of bad luck, any that you can find on the net that add any -1
1) Bad luck, 2) worst luck, 3) No luck, 4)jinxed, etc...can't remember all of them off hand
Most don't have a benefit, but 2 add either 3 quricks(sp) or 1 feat(choose feat)
4th) add 5 feats
1)Area jinx, 2)Metamagic: widen spell(a prereq), 3)blast of jinx, 4) The 4th feat is where you can spend your action/hero points to pass your, 5) can't remember
5th) Have your Deity/God be of travel/ luck/ thievery - basically any that allows you to state that you are rolling a pair of dice to take the best, instead of just one!
You should be able to roll about 4 to 6 dice, just by activating your deity/god. Then take the best pair, but take the worst roll out of the best pair
All together you have about 60-70 feet diameter of bad luck you can now pass to anyone at a penalty of -13 to -14
Then just to be really bad add on top of this abomination the 9th; 10th; 11th trait of:
9)"Born under a bad sign" which is -1 to all saves and -1 hp/lvl, but no auto death and nothing below 1 hp
the return of this is that you get a 4th, 9th, 15th lvl invocation that is not eldritch, unless you have a warlock class; then you can choose a +1d6 eldritch blast instead
10)"Corruption at level 3" --> this you will have to work with your DM to understand, but it states: "however the outcome of the roll is, it comes out at the least likely way"
Think of this as a "who lines is it anyway: scenes from a hat", but the more unlikely it is, the more the DM can apply an up to a -3 penalty as long as there is no auto-deaths or fails and the DM applies them where the negatives are likely to be.
11) "Wrath of God/Goddess/Deity/etc" First set this to "bad/strange luck" -1 to rolls no auto-death/fails, but you have managed to incurred someones ire
Finally add the feat: "Bad Mojo" from the fortune's fool - Not only do you get 3 more luck rolls, but you can spend those rolls to cast a curse or your own bad luck on to a target and that is full bad luck per effective character level!
This creates -19 to rolls (mostly saves) and about 9 times you can literally shoot your bad luck on any choice.
To start the jinx you need about a 4th level arcane caster(any type), can't have any lucky traits, and the fool part you need a 4th level too.
Sorry for the long wind, but I wish I could credit others for this crazy concoction and loved explaining as best as possible.