At what velocity must a cuber move to kill a bison?

Hey I built a potato cannon, and I realized that a potato was a bad projectile, so I modified the cannon and used a cuber, and I already managed to shoot a cat of my neighbours roof, but I also want to kill his pet bison due to a fight long ago about who should have the most garden gnomes. The entire ordeal lead to a court battle and i ended up getting sued for the bison. then he claimed it.... I want revenge... if I don't get the bison, than at least nobody gets it!!! long live the potato union!