Mule, Too
Two German soldiers (and a mule) wearing gas masks in WWI, 1916. Early gas masks were crude, as nobody thought or expected that poisonous gasses or fumes would ever be a weapon. Now, poison gas is only one of the invisible threats that soldiers face.
And what good is a mule if it’s gassed? That was probably their mode of transportation to travel long distances. And speaking of poison gas being only one of the invisible threats, there are way more gasses out there that can subdue an enemy. If it weren’t for masks, some battle would be over way before they even started.
