Venomize

You coat a weapon or pieces of ammunition with a layer of venom. The next time you hit with that weapon, you may force the target to make a Constitution saving throw or take an extra 2d12 poison damage from the attack, taking half damage on a success. The venom disappears once a creature has been forced to make the Constitution saving throw.

The poison damage increases by 1d12 for each level spell slot higher than first.