Facing the target

Greetings! I have a problem with my traps . While my knifes that have to face towards to my player like with transform.lookat(myvariable); and my knife just stand there and rotate by facing to the player position so after sometime it will instantiate and i can use addforce later to damage player when collide with knife but when i use lookat function then when game starts the knife stands with 90 degrees of anger and does no even face on it(I think there must something other to face the knife to player) and knife just stand there with a 90 degrees angel upwards . Please help me to solve this .