Boomrat has a name which has pretty simple origin: Boom+Rat.
But I really don't get what's the origin of 'thrumbo' and 'Xerigium'.
Anyone knows about it?
Just guess would be appreciate.
Xerigium is probably
xenoginseng
Eryngium (https://en.wikipedia.org/wiki/Eryngium) is a type of thistle (and Xero- is greek for "dry" which might not have anything to do with it). The in-game sprite looks a bit like a thistle.