The man suing Gwyneth Paltrow over a 2016 collision at one of the most upscale ski resorts in North America took the witness stand on Monday as the closely watched trial goes into its second week in Utah.

Terry Sanderson, 76, recounted a ski collision that he claims was caused by Paltrow, 50, causing four ribs to fracture and head trauma that he claims manifested as post-concussion syndrome.

The retired optometrist said he heard a “blood-curdling scream” soon after passing “slow it down” signs on the slope: “It was like like some was out of control and about to hit a tree and die.”

“I got hit in the back so hard … a serious, serious smack,” Sanderson testified. He said he was propelled into the air and saw “a whole lot of snow. I was flying. Last thing I remember everything went black.”

Then next thing he realized, Sanderson said, was that someone was “mad at me” and shouting: “Do you realize you weren’t skiing under the rules?”

Sanderson said he felt that he was being made in the “bad guy”.

“Just a very angry person trying to bully me in believing it was my fault,” he said.

At the start of the trial, Sanderson’s attorney told the court that Paltrow had screamed before the collision and then “bounced off” Sanderson, who was left unconscious.

Sanderson said his injuries from the collision had left him physically and mentally impaired. “I’m living another life now,” he said. He said his right leg had “its own ideas of where it needs to be” and can no longer ski.

If he did, and had another crash, he could “end up in a nursing home” and had been told the odds of that were “very high”.

Mentally, Sanderson said, he had “big gaps” in his thinking. He said: “It’s like I’m building a case and they don’t know what I’m talking about until I get to the subject. Everything is backwards … it feels like I can’t connect.”

Craig Ramon, the sole eyewitness of the crash, earlier testified that he heard a loud scream and saw Paltrow hit Sanderson, causing his skis to fly up into the air before he plummeted down on the beginner run in a “spread-eagle” position.

Ramon’s version differs from the one Paltrow and her legal team have told. Immediately after the crash, the court has heard, Paltrow’s ski instructor yelled at Sanderson: “What did you do? What did you do?”

On Friday, the Oscar-winning actor testified that two skis came in between her skis, forcing her legs apart. She said she then heard a “grunting noise” and a body pressing against hers before both skiers fell into the snow.

Paltrow said she thought for a second that the collision was a “sexual assault” because “he was making some strange noises that sounded male”.

Paltrow said she did not ask about Sanderson’s condition after the collision but stuck around “long enough for him to say that he was OK”. She said she was upset by the accident, and after lunch had taken to rest of the day off from the slopes and scheduled a massage.

The trial, like the Johnny Depp-Amber Heard defamation trial last year, has become fertile ground for internet commentary, social media clips and memes focused on Paltrow’s turn on the stand.

Sanderson had initially sued Paltrow for $3.1m, but later amended his complaint after punitive damages were ruled out by Judge Holmberg. He has amended his claim to $300,000.

Paltrow is seeking $1 in damages, a small fraction of the $8,800 she paid to take her family skiing that day. But she is also seeking legal costs, which could run into tens of thousands of dollars.

It is likely TV producer Brad Falchuck, then Paltrow’s boyfriend and now husband, and her children Apple Martin and Moses Martin, will be called to testify on Paltrow’s behalf.

But all eyes will be on Sanderson. Under cross-examination, Paltrow’s attorneys are likely to repeat claims made in court documents that his lawsuit amounts to an attempt to exploit her celebrity and wealth.

After the accident, Sanderson circulated an email with the subject line “I’m famous”. The email included a now-missing GoPro video.

On Monday, Sanderson acknowledged he had sent the email. “I’m not into celebrity worship,” he testified. He said he had only been trying “to placate” his daughters.

“I didn’t pick my words very well,” he said. “I was trying to add levity, and it backfired.”

Paltrow’s lawyers will also likely question Sanderson on the post-concussion symptoms medical experts and his doctors testified about last week. On the stand, Sanderson’s daughter, Polly Sanderson Grasham, 49, described her father as “a goer” before the crash, but said he had subsequently become disengaged.

“I almost expected drool to be coming out of his mouth,” Grasham said.

Under cross-examination, Grasham confirmed Sanderson had been obsessed with the incident. Questions about whether he was an abusive father have also been raised and it was noted that after the ski collision he took trips to Europe, Peru, Morocco, the Canary Islands, Thailand, and zip-lined in Costa Rica.

“Is it fair to say his travels did not suffer as a result of the accident?” Paltrow’s attorney, Steve Owens, asked.

“His travel companions might have suffered,” Grasham responded.