Among the different kinds of clipped coins is a rare type called a Strike Clip. It occurs when a planchet is sheared into two pieces by a collar die that is stuck in the up position (frozen collar) and acts as a Guillotine. When struck, one piece of the coin results in a Curved Strike Clip while the other becomes an Elliptical Strike Clip. These types of clipped coins are not conventional (where most clipped coins are a result of the blanking process which happens far earlier in the minting process).
Here is a fantastic specimen that illustrates both types of striking clips and how it happens. It is a 2007 Egyptian 50 Piastres that was nearly sheared in half.
In this case the 50 Piastres was positioned 30% off-center when struck. The imparted reeding from the frozen collar die after impact is impressive. Had the collar die cut completely through, that portion of the coin that is unstruck would be our Curved Strike Clip while the other portion with the die-struck design of Cleopatra would be our Elliptical Strike Clip. If not for both the thickness and very hard composition, (a brass plated steel planchet), it most assuredly would have separated into two pieces.
It is important to understand differences between the many types of clips, and Strike Clips are the rarest of them all.