Self-destruct

self-destruct 
Self destruct (Action operator) 
Causes the specified ship(s) to self destruct. 
Takes 1 or more arguments... 
All: Name of ship to self destruct. 

• It should be noted that there is a difference between the FS1 SEXP and the FS2 SEXP. While the FS1 SEXP brings the ship's hull straight to zero immediately, the FS2 one brings it down successively.
• In FS1, ships which were destroyed via self-destruct would be shown as 'Destroyed' in the F4 Mission Log. In FS2, they are said to have 'Self-Destructed.'
• This triggers the ship's destruct animation rather than making the ship disappear, if that is what you meant to do, there are better SEXPs (ship-vanish).
• Self-destruct will not always trigger the (is-destroyed-delay "Ship that self-destructs") SEXP tree, so it is safer to circumvent it by using the (is-event-true-delay "Event that triggers self-destruct").