As with many customs, traditions around Karneval are regionally different. The Hemdglonkersumzug (parade) is one such custom that is only part of the Swabian-Alemannic Fasnet and takes place mostly in Württemberg (of the state Baden-Württemberg), near Lake Constance and the Black Forest region.
Hemdglunkerumzug in Kollnau. Photo: Von James Steakley - Eigenes Werk, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=145184013
The Hemdglonkersumzug takes place in the morning or the evening of Schmotziger Dunschtig (Fat Thursday). People get dressed up in white nightgowns and white night caps, some even painted their faces white; they are the Hemdglonker (various spelling).
Hemd means shirt and a Glonker is somebody who sits around a lot, is lazy and generally good-for-nothing, so not exactly something you want to be. But it's Fasnet and everything is upside down, women and/or jesters take over town halls and in Constance students make fun of their teachers on large posters and banners that they carry with them in the Hemdglonkersumzug.
The people in night gowns also carry with them noise-makers like lids, ratchets, whistles etc. Streets are often decorated with Fasnachtsbändel, ropes with colorful pieces of cloth spanning across the streets (often the parades lead through old parts of town and are narrow pedestrian zones).
The large figures resembling the human Hemdglonker are called Gole after Goliath and are carried during the parade.
If the Umzug takes place in the evening, people will often attend parties afterwards. Needless to say, business-wise not much gets accomplished during Fasnet.
Hemdglonkerumzug with Gole in Radolfzell. Photo: Von Hemdglonker - Eigenes Werk, CC0, https://commons.wikimedia.org/w/index.php?curid=160773312