There are 2 Friar Rushes: Friar Rush and Friar-with-the-Rush. The latter is often confused with the former. Friar Rush refers to an indoor spirit which would try to get monks and friars to stray from the path of God (namely to get drunk and party). Friar-with-the Rush is a local name for the Will-o'-the-Wisp in the British Isles. A Rush (German Rausch) is a household spirit, not a field spirit, so Friar Rush as a Will-o'-the-Wisp is a mistranslation, one which is a common one made for hundreds of years. The non-Will-o'-the-Wisp Friar Rush is from German folklore.