Invasion is a 1975 horror novel by American writer Dean Koontz, originally released under the pseudonym Aaron Wolfe.

[1] The story begins with a thirty-two-year-old Los Angeles police officer named Jack McGarvey.

With shotgun in hand, he opens the door and sees the traveler piggybacking on his late wife's corpse, taken from the family plot on the ranch.

Travis Potter discovers Eduardo's body and an autopsy determines he suffered a heart attack.

They are looking forward to a quiet life in Montana, away from big city crime and a safe place for Toby to attend school.

Heather discovers that bullets do not damage the Giver riding Eduardo's corpse, so she sets the house on fire, hoping the flames will destroy the creature.

Jack is picked up by a snowplow driver, Harlan Moffit, and sees the house on fire when they pull in the driveway.

Heather and Toby are carrying gas cans up the back stairs, and Harlan assists the family when Jack tells him of an alien invasion.

They carry the gasoline cans to the caretaker's house and see a third entity, riding another corpse, held immobile by Toby's imagination.

After the authorities have taken everyone's statement, Toby tells his father that, at the very end, the Giver sprouted off a few small worms that tried to escape by boring into the wood.