Ninja (Fallout: New Vegas)

Ninja is a perk

Effects
When attacking, one gains a +15% critical chance on all Melee and Unarmed attacks. Also, critical Sneak attacks do 25% more damage than normal.

Bugs
Ninja multiplies your critical chance by 1.15 instead of adding a flat 15%, unlike all other perks/traits that modify critical chance. For example, a character with a critical hit chance of even 25% would have it be increased to only 28.5% rather than to 40% as it should. (25% * 1.15 = 28.75% vs 25% + 15% = 40%)