A Royal Marines dropout armed himself with combat knives and roamed the countryside hunting for people to kill before stabbing a walker to death, a court heard.
Moses Christensen, 22, is accused of murdering 70-year-old Richard Hall in a random savage attack on Brown Clee Hill, in South Shropshire on August 13 last year.
He repeatedly plunged a serrated double-bladed knife into the face, neck and chest of Mr Hall "just for the sake of it" after their paths crossed at the popular beauty spot, a court heard.
Christensen told police how he was overcome with a "strong desire" to kill the pensioner after they greeted each other with a s
mile as they met at the foggy summit, his trial has been told.
He also described to officers how he carried out the "very savage, animalistic and brutal" killing and even "stabbed him one last time to make sure he was dead", Stafford Crown Court heard.
Christensen, of Oldswinford, Stourbridge, West Mids., admits carrying out the stabbing but denies murder and went on trial today.
The jury was told how Christensen had intended to go on a killing spree and had been plotting a massacre for several months.
He bought two deadly blades on the internet and had previously used one to kill sheep to eat whilst living rough in the countryside.
But his worried parents contacted police when he began talking about his desire to kill and also take revenge on his old school teachers and their children, jurors heard.
The court was told by the time officers found him he had carried out the alleged murder after scouring the local area looking for individuals or small groups of people to kill.
Opening the case, prosecutor Adrian Keeling QC said Christensen came across complete stranger Mr Hall by chance and killed him because he was an "easy target".
“This is a particularly dangerous young man and you can be properly sure that what he did on that day was murder rather than anything else," said the lawyer.
Mr Keeling described the defendant's background as potentially "troubling", with his parents having separated when he was 13 before he began suffering with depression.
In 2018 he set about training to join the marines and passed all the entry tests though eventually withdrew his application due to fears he wouldn't fit in socially, Mr Keeling explained.
The defendant's behaviour "became increasingly unusual" after this point and he even spent time living rough in the countryside and killed sheep to eat, he said.
Christensen "spent a lot of time" playing violent video games and spoke about suicide, before taking up boxing, Mr Keeling continued.
The court heard how the defendant spent the first period of lockdown last year with his grandmother before camping with his mum for a few days when restrictions were lifted.
"The defendant began to say things to her that really worried her," said Mr Keeling.
“In a casual way, he spoke of a desire to kill three of his teachers and the daughter of one and eat the flesh of one in front of the other."
He had told his parents he had kept himself in shape for a killing spree but feared being "hunted down", the prosecutor said.
On August 8, the defendant's mum called the West Midlands Police crisis team "and was trying to get him seen", but it was later agree the defendant's dad would try to persuade him to co-operate with psychiatric intervention.
However, Christensen refused and told his father "nothing further to say, goodbye" before picking up his army boots and leaving, said the prosecutor.
Police began searching for him but he wasn't seen again for five days, by which point Mr Hall had already died.
The court heard Christensen disposed of the knife and went to a nearby house around 8.30pm and asked the occupants to call police so he could confess.
Mr Hall had gone out for a walk around 3pm.
Christensen later "described with some precision" where to find the pensioner's body.
Examination showed Mr Hall had suffered numerous stab wounds to the face, neck and chest, his heart was damaged and his liver and lungs.
Christensen then gave a "full but chilling" account of what happened, said Mr Keeling.
Referring to Christensen's account, the prosecutor said: "I would like to point out first of all this murder wasn’t just an outburst of emotion, it wasn’t spontaneous, I had planned to kill people."
But having stabbed his own arm during the attack, Christensen realised his plan to conceal the body and go on a "more obsessive killing spree" was scuppered, the jury was told.
Asked by police if he regretted the killing, he said "he would rather murder and be killed than participate in society", added the prosecutor.
The trial continues.