The Helio Rat'ler (as in Rattlesnake) was an agricultural spraying aircraft to be produced by Helio Aircraft. Only a single prototype was produced (registered N4405S), featuring the wings and tail of a Helio Courier on a new, low-wing fuselage, and a Lycoming IO-720 eight-cylinder engine producing 400 horsepower.
References
Helio Rat'ler Wikipedia(Text) CC BY-SA