So I started by getting fobwatch from the creative menu, then I went into the TARDIS and activated the chameleon arch by right clicking it and storing 12 regenerations in biological upgrade.
Next I shift-clicked a villager, a cow, a sheep and a pig (I had several biological upgrades all with 12 regenerations) and proceeded to kill them.
They died without regenerating.
So I started by getting fobwatch from the creative menu, then I went into the TARDIS and activated the chameleon arch by right clicking it and storing 12 regenerations in biological upgrade. Next I shift-clicked a villager, a cow, a sheep and a pig (I had several biological upgrades all with 12 regenerations) and proceeded to kill them. They died without regenerating.