Piers Polkiss was a Muggle and Dudley Dursley's best friend. Despite being scrawny with a face like a rat, he was a member of Dudley Dursley's gang and was usually the one who held people's arms behind their backs so Dudley could hit them. Piers did not like Harry Potter, because Dudley did not, and he always followed Dudley's lead. Piers would also join Dudley at Smeltings Academy.[1]
On 23 June1991, Dudley's eleventh birthday, Piers accompanied him, the Dursleys and Harry to the zoo. During the trip, Piers saw Harry talking to a snake in the reptile house. When Harry was pushed out of the way, and then unintentionally made the glass disappear, Piers fell into the enclosure with Dudley. When Piers told the Dursleys that Harry had been talking to the snake, they gave Harry his longest ever punishment.[2]
During the summer of 1995, Dudley lied to his parents saying that he was at the Polkisses' having tea, although Piers was with Dudley's gang as they roamed the neighbourhood, bullying younger children.[3]
Etymology
Piers is of Anglo-Saxon heritage and means "rock." It is a variant of Peter, from the Greek for "rock." Polkiss may be a variation of Polk, which itself is a variation of the Scottish names Pogue, Pollack, or Pollock, meaning "from the pool or pit."
It is mentioned several times in the books that all the members of Dudley's gang were big and stupid, but Piers was always described as being scrawny with a face like a rat. It is possible that Piers was scrawny when compared to the other members or that he gained a significant amount of weight after he went to the zoo with Dudley and Harry.