Gage Creed is the main antagonist of Pet Sematary. He was Louis and Rachel Creed's 3-year old son. While they were at a picnic Louis was playing with his son with a kite but when the kite fled towards an upcoming truck, Gage was hit and killed. Louis devastated by his death would always have nightmares of not being able to save him that day. Gage suddenly comes out from the dead, to come to his family's house, killing them one by one but was killed by his father with a shot, with him injecting it through his neck causing Gage to die.
Before Gage died he was pure, innocent, playful, loving, carefree, and sweet who hade a close-relationship with both his parents, most closely to his dad, who he loved the most. After Gage was killed and came back from the dead, he revealed to a more evil side being a murderous, cold, still playful, and evil 3-year old who killed half his family.