If you're looking to Download Mantis on your Chromebook laptop Then read the following guideline.

Mantis is a plugin that emulates a rare BBD (bucket-brigade device) delay/echo unit of the 70s, faithfully recreating its warm and analog sound. Available as AUv3 and Standalone. As the original unit, Mantis features an echo section with four taps and four swell selectors. It also features the rotafaze section, a modulation that can mimic the wow/flutter of a tape echo or turn the unit into a unique chorus-delay.