Formal:
* The constant barrage of regulations stultified innovation within the company.
* The oppressive heat stultified any thoughts of going outside.
* The author's overly complex prose stultified the narrative, making it difficult to follow.
Informal:
* That boring lecture really stultified me. I couldn't stay awake!
* The endless paperwork stultifies my creativity.
* My boss's micromanagement stultified any sense of autonomy I had.
Figurative:
* The lack of sunlight stultified the growth of the plants.
* The constant negativity stultified their hopes for the future.
Remember: "Stultify" implies a process of being made dull, inactive, or unproductive. It carries a negative connotation.