Glider destruction

Glider destruction of a target pattern is accomplished by hitting the target pattern with gliders that can be rewound arbitrarily far back in time.
In a sense, glider destruction is "the opposite" of glider construction: a glider synthesis is a recipe for constructing the target in surrounding empty space; a glider destruction is a recipe for reducing the target to empty space.
In Conway's Game of Life, for many target objects, glider destruction is significantly easier than glider construction. For example, out of all still lives with 11 or fewer alive cells, only long ship, canoe, very long ship and loaf siamese loaf cannot be cleanly destroyed by a single glider; all of these still lives have 2glider destructions. Only three out of 12bit still lives (shiptie, long^{3} ship, long^{6} snake) require two gliders for clean destruction.
Cleanup in staged glider synthesis
Some of the most efficient known glider syntheses for various objects require additional gliders to clean up any extra objects produced along with the target, for example this 5G synthesis of cisboat with nine:
A fiveglider synthesis of cisboat with nine, featuring glider destruction of a block (click above to open LifeViewer) 
Related problems
As of September 2023, the following questions are unsolved:
 What is the smallest still life without a twoglider destruction?
 Is there a target that is cleanly destroyed by any single hitting glider?
 Is there a "gliderproof" target that can withstand a collision with any single hitting glider?
 Is there a finite target that cannot be destroyed by an unidirectional slow salvo of single gliders?
 Is there a finite target that cannot be destroyed by any number of gliders from any directions, one glider at a time?
 Is there an "invulnerable" target that cannot be destroyed by any interaction from outside?
 Is there a target where every collision between it and a single glider settles into ash with a higher population than the target?
A 8492bit still life is known (long^{4243} ship), such that every collision between it and a single glider settles into ash with lower population.^{[1]}
See also
 Lifeline Volume 7, page 1
 Engineered diehard
 Seeds of Destruction
 Flyby deletion
 IceNine
 Tutorials/Glider syntheses#Assisted cleanup
References
 ↑ Goldtiger997 (February 4, 2023). Re: Unproven conjectures (discussion thread) at the ConwayLife.com forums
External links
 indestructible pattern (discussion thread) at the ConwayLife.com forums
 Indestructible object it’s time we answer the question (discussion thread) at the ConwayLife.com forums
 Glider Destruction Of Still Lives, Oscillators, Etc. (discussion thread) at the ConwayLife.com forums
 Structures resistant to attack (discussion thread) at the ConwayLife.com forums
 Re: Life has been proven omniperiodic. What next? (discussion thread) at the ConwayLife.com forums