The far end of the tunnel was filled with gas that wouldn't dissipate. The poisonous haze had no effect on me, other than its foul smell. This allowed me to investigate the area, where I discovered a canister which had broken off the Burrower as it angled upward and out of the tunnel. I remember reports of previous Burrower sightings, and none of them mentioned a poison emitter. This gas performs a secondary mop-up duty -- by seeping into nooks and crannies, wafting its way deeper into human habitats, and indirectly killing what wasn't in the Burrower's original line of attack. What I found most terrifying was, this was just another example of how the Chimera have evolved to more efficiently kill their stubborn enemies.
-- Journal Entry, 03 September, 1951 -- James Grayson