There are several ways to kill bed bugs instantly, including:

1. Bed bug spray: Bed bug spray containing pyrethrin, an insecticide extracted from chrysanthemums, is lethal to bed bugs and can flush them out from hiding places.

2. Rubbing alcohol: Diluted rubbing alcohol can be sprayed directly on infested areas to kill bed bugs almost immediately. However, it only works on direct contact with the bug and may not kill eggs or nymphs.

3. Tea tree oil: Tea tree oil is an effective natural remedy to kill bed bugs instantly. It can be sprayed on furniture joints, headboards, cracks, and corners after being diluted with water.

4. Diatomaceous earth: Diatomaceous earth is a chemical-free powder that can eliminate bed bugs by dehydrating them. It may take up to a week before seeing results, and it should be used with caution as it can be easily inhaled.

5. Bleach: Bleach can kill bed bugs instantly. Clothing and other items can be washed with hot water, bleach, and detergent, followed by a cycle in the dryer at the highest heat setting possible. A potent spray can also be created by mixing equal parts hot water and bleach.

6. Heat or cold: Temperature is an effective way to get rid of bed bugs in a mattress or other important area. Affected bedding or clothing can be washed in very hot water for 30 minutes, or put in a freezer that is at least 0 degrees Fahrenheit for four days to make sure all bed bugs are dead. Steam can also be used on mattresses, couches, and other places where bed bugs hide.

Its important to note that while these methods can kill bed bugs instantly, they may not be effective in eliminating the entire infestation. Its recommended to use a combination of methods and to seek professional help if the infestation is severe.