As a result of Patrice's curse, the normally docile plant started to accost humans. Those who came in contact with its corrosive excretions would writhe in agony as they dissolved, starkly reminding all of the terrible cruelty of demonkind. The plant contined unabated in its rage, reducing everything it saw to fertilizer.
See Acid-Spitting Plant.
An acid (from the Latin acidus/acēre meaning "sour") is a chemical substance whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals (like calcium) to form salts.
Boss in 10th Chapter during Half Life Odyssey Event.