Sunblade

Appears to be a simple hilt, but use a bonus action and a blade of pure radiance appears. While it exists it has Finesse property.
This weapon deals radiance damage and an additional 1d8 damage against Undead
The blade emits bright light in a 15' radius and dim light for an additional 15' radius. The light
is sunlight. You can use an action to expand or reduce this radius by 5' with action, up to 30'
and as little as 10' .