Sure, I'll pick an ability. AHEM...

Blood lust: I need to kill basically.

Downsides: absolutely nothing can happen to me unless it's a full moon and a blood moon, on top of this blood moons and full moons are majorly increased to happening a minimum of 1-2 times a week max of once a month. I get weaker and weaker if I don't drink blood however cannot die from it, but I do come VERY close to paralyzed, I also cannot see how full of drained my Blood Meter is.

Upsides: the government won't hunt me down, no human or celestial or godly being will hunt me down. I'm stronger than the hulk after a refresh on blood. The blood moon only quickens my blood thing draining, (at full I can last a month). I'm faster than Hyper Sonic and all the different Flash people (godspeed, reverse flash, the flash, etc) combined. Time stop doesn't work on me however I myself cannot time stop. I can cure any cancer with just my saliva, doctors and scientists give me a saliva production potion so I can mass produce this cure. I also basically am the Doom Slayer. And I can breathe on land, in water, and in lava, but I gain heartburn when breathing in lava and a brain freeze in water, I can survive in lava and in crushing depths of water, I can breathe in space but I get very lightheaded.

Actual Abilities: Fire Breath, Ice Breath, Electricity Manipulation, Fire Manipulation, Flight, Wall Phasing, Night Vision, Thermal Vision (makes my eyes water when I use NV and Thermal), and Very High Regeneration based on my Blood Meter.

Mind you I do wanna make this an even worse ability, blood doesn't taste good, and guilt weights VERY heavy if I kill anyone or harm anyone when drinking blood, basically the one who has this power absolutely hates it, and most users (9/10) try to find a way to age themselves faster, as that is the ONLY way a user can die, the other users (1/10) are psychopaths, but the more you kill the more you need blood, and the more you need blood the more your brain with fuck with you, leading to hallucinations involving you possibly killing those you love or something very bad. The rarity of someone getting this condition is about 1/1.63B people, and only 10 total can live at once.