Due to your time in a pocket dimension, you may convert any medium or smaller objects you alone are holding into a Tiny object. The objects maintain their normal properties, and return to their normal size as soon as you stop touching them. 

If you attack a creature wearing armor with a melee attack, you have advantage on the attack roll.

You have Darkvision up to 30ft. 

If you take the dodge action on your turn, you may then use the dash action as a bonus action. Whenever you dash, you do not take opportunity attacks.

You have advantage on Wisdom (Perception) checks that rely on smell.

Being an awakened mouse has some limitations. When making a character, regardless of the rolled stats, you canot exceed the min or max requirement for the stat, and replace the assigned stats with the listed requirement instead. Magic items can ignore these restrictions.

You cannot have strength greater than 4.
You cannot have intelligence less then 10.
You cannot have a con modifier exceeding 16.
Your dexterity can go up to 22.

Additionally, as a mouse, you are able to fit into hole or space that is at least 1 inch in diameter.

You know Common and one language of your choice. Additionally, you can communicate with any rodent.