The Hummingbird is, at heart, a hard and choppy tremolo. What comes out is more akin to vintage synth style oscillations. It's core is based on the old Vox Repeat Percussion with several updates to reduce noise, enhance the "chop" and add more control. It can create ring mod-like octaves, slow pulses, ping pong delay-like stutters, light blipping through machine gun stutter tremolo and many more wacky sounds! Available at JetCityMusic.com.
http://www.jetcitymusic.com/index.php?page=shop.product_details&flypage=vmj_naru.tpl&product_id=245&category_id=46&manufacturer_id=19&option=com_virtuemart&Itemid=89