You searched for: “petrify
petrify (verb), petrifies; petrified; petrifying
1. To convert or to change something into rocky substances: In order to petrify wood, there needs to be an environment without oxygen, but with minerals, which then fill the cells of the tree and convert it into a very hard material, such as a stone.
2. To paralyze someone with astonishment, horror, or another strong emotional situation that makes someone rigid or unable to move: Jack was totally petrified and speechless when he lost his job and his wife at the same time.
petrify, putrefy, purify
petrify (PET ruh figh") (verb)
1. To change into stone or a stony substance: Over thousands of years, the buried tree trunk will gradually petrify into rock.

Chad's icy glare served to petrify Debora and she was unable to run away.

2. To confound with amazement or fear: The harrowing tales of the author will petrify Janine and she will not want to walk in the graveyard after dark ever again.
3. To deaden or to stifle: Betty had the feeling that the long lecture was going to petrify her mind because it was so boring.
putrefy (PYOO truh figh") (verb)
To create a state of rottenness, physically or morally: If you bury the garbage, it will putrefy and eventually become compost.

Nathan was so evil he seemed to putrefy everything around him.

purify (PYOOR uh figh") (verb)
1. To sanitize or to clean: The brisk winds seemed to purify the air in the city.
2. To free from guilt or blemish: Rosetta's confession that she took her mother's ring helped to purify her conscience.

Howard wants to purify the air because the old cabbage has started to putrefy and to stink up the place and if he smells it for very long, he's afraid his brain will petrify.