race features:
Slight and swift, you possess the following traits:
Darkvision
Mousefolk have superior vision in dim light and darkness. You can see in dim light within 60 feet of you as if it was bright light, and darkness as if it was dim light. You can't discern color in darkness, only shades of gray.
Lightfooted
You have proficiency in the Stealth skill.
Scurry
You can move through the space of any creature that is medium size or larger, as if it were difficult terrain.
Squeeze
You suffer no penalty for squeezing into a space that is only large enough for a creature that is one size smaller than you.
Brave
You have advantage on saving throws you make against being frightened.
Mousefolk Lineage
Mousefolk either belong to the lineage of Mouselings or Ratlings. Choose one of the following options, depending on your lineage:
Mouseling's Sidestep
When a creature you can see makes an opportunity attack against you, you can use your reaction to impose disadvantage on the attack roll.
Ratling's Gnaw
You can use your action to chew through and break a small nonmagical object that isn't being worn or carried, like a rope, a wooden rod or handle, or a length of frabric. If you chew on a wooden wall or floor for 1 minute, you can gnaw a hole large enough for a tiny creature. You can't chew through materials that are harder than your teeth, such as metal, stone or crystal.