The Knockout Dive was Drake Cooper's invention. It was originally called the "Fast Attack Dive Move". It was renamed in Sly 2 to Knockout Dive.It is well known throughout the series, and is the most basic combat power-up in all three games. It is also the first safe move in Sly 1 and 2. However, in Sly 3, there are no bottles, and thus, no safes. So you buy it like any other power-up.
Sly Cooper and the Thievius Raccoonus
In Sly Cooper and the Thievius Raccoonus, the Fast Attack Dive Move was the first move that you got from a safe (it doesn't matter which safe it was). It was used to quickly dive forward while Sly spun his cane, and was used as an attack. It was later upgraded to allow you to dive from the air, collecting coins that were in the shockwave radius, and was the fourth move obtained from a safe.
Sly 2: Band of Thieves & Sly 3: Honor Among ThievesIn Sly 2 and Sly 3 the move was called the Knockout Dive and was used very similarly to the Fast Attack Dive Move. One difference; since the enemies were no longer one-hit, Knockout Dive would not kill the enemies, but just knock them out, allowing Sly to use his stealth slam or simply run away.
Also in Sly 2, The Insanity Strike gadget will only work if you knock out the enemy. If you equip the Insanity Strike, then use the Knockout Dive, the guard will attack other guards guaranteed.