The Oomph (Ranaincumbramentum alvinschwartzi) is a Fearsome critter that is said to be about the size of a dog, but is a cross between a big lizard and a toad with long claws and with sharp spikes all along its back and big spots all over it. It goes around hunting for eggs in birds nests, and when it finds one, it makes a noise deep down in its throat that sounds like ‘oomph, oomph.’
Further reading[]
"The Oomph" from Yarns of the Big Woods (1922-1295) by Art Childs