The Ambush on Peter Parker was a failed attempt by Shocker to prevent Spider-Man from interfering with Vulture's plan to hijack the Stark Cargo Plane.
After Tony Stark had revoked the Spider-Man Suit, Peter Parker returned to his high school life, and asked Liz Toomes to be his date for the homecoming dance. Parker arrived at the Toomes Residence to pick Liz up when he was greeted by her father, whom Parker immediately recognised as the Vulture. Toomes made small talk with Parker and then offered to drive them both to the dance despite Parker's protests.
During the drive Toomes asked Parker about what his plans were post-graduation. Liz explained to her father that Parker was only a sophomore but that he held an internship with Tony Stark.
Toomes' interest was piqued further when Liz declared that Parker was even friends with Spider-Man. When Toomes asked what Spider-Man was like, Parker fumbled, prompting Toomes to ask if they had met before, stating that Parker's voice was familiar to him, as if he had recently heard it somewhere. Parker responded that they had never met, ending their conversation.
However, Liz carried on about how Parker came to their house party and left after a few minutes and then mysteriously disappeared during the Decathlon. Realising that the Chase of Adrian Toomes' Crew was on the same night as the party, Toomes suspected that Parker might be Spider-Man and inquired how Parker felt to have been saved by Spider-Man at the Washington Monument, only for Liz to declare that Parker was not with them.
Toomes' suspicions about Parker's true identity were confirmed, although he kept his observations quiet and inconspicuous. Once Liz exited the car upon arrival, Toomes told her to give him a few minutes alone with Parker as he wished to give him the "dad talk".
Once she left, he pulled a gun out from the glove compartment and confronted Parker about asking him whether Liz was aware of his duality and sparing his life, as gratitude saving her life.
He then gave Parker an ultimatum; to stop pursuing him or else he would kill him and everybody he loved, and then prompted Parker to thank him for the deal he had offered.
After Parker left the car to join Liz inside the school, Toomes contacted his partner Herman Schultz to make sure Parker adhered to the deal.