Arcumvita

This small, six-inch long ebony rod feels cold to the touch. You can use a bonus action to speak this magic rod's command word, causing spectral white ribbons to expand from each end of the rod, forming a strung bow. When the string is pulled back to shoot, a spectral arrow appears, ready to be fired. All other arrows pass through the string. The spectral arrow deals 2d8 force damage to any target it hits. The bow lasts until you use a bonus action to speak the command word again or until you drop or store the rod. 

An amount of arrows equal to half your Constitution score, rounded down, plus your Constitution modifier can be fired from this spectral bow each day. You can push that limit, at the risk of exhaustion. For each additional arrow fired beyond that limit, make a Constitution saving throw. The DC is 10 + 1 for each arrow fired beyond that limit. On a failed saving throw, a character suffers one level of exhaustion. At dawn the next day, the arrows are replenished.

The disadvantage on attack rolls imposed by exhaustion is ignored for the attack rolls of this magical bow.

Proficiency with a Longbow allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Damage: Force, Damage, Combat, Ammunition, Heavy, Range, Two-Handed, Slow