releaser

[ri-lee-ser]

noun

a person or thing that releases.
Ethology. a key stimulus, as a sound, odor, moving shape, or patch of color, that elicits a predictable behavioral response in an animal.

Origin of releaser

1425–75; late Middle English. See release, -er¹

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

One day she sang of Death the releaser, and Ruark thought, ''Tis come!
The Shaving of Shagpat, Complete
George Meredith
If such music-making is ever to become accepted, then I long for Death the Releaser.
Ivory Apes and Peacocks
James Huneker