General:
* The spies were tasked with infiltrating the enemy's headquarters.
* The protesters infiltrated the building to deliver their message.
* Rumors began to infiltrate the office, causing unease among the employees.
Figurative:
* The rain infiltrated the tent, leaving us soaked.
* The internet has infiltrated every aspect of our lives.
* The virus infiltrated the computer system, causing widespread damage.
Formal:
* The government infiltrated the terrorist organization to gather intelligence.
* The scientist infiltrated the bacteria into the solution to study its growth.
Informal:
* My little brother infiltrated my room while I was out, leaving a mess everywhere.
* The smell of fresh-baked cookies infiltrated the entire house, making me crave one.