Easter is here, Good Friday today.
Looked up a bit of folk believes, and traditions related to this particular day within the greater holiday of Easter, which actually starts 40 days before, with the Great Fast.
One group of customs is a type of health conjuration, all related to water, more specifically to fresh stream/brook water. Most often is bathing in it, washing oneself, just face or fully submerging in it. Sometimes done at early dawn. It could help with various ailments, give beauty, or just health in general. It should help with animals too, either the through should be filled, or the animals has to be led into the water. I like the one where girls seek out places where willow trees grow next to the water for bathing in it results in long, thick, healthy hair (on their scalp).
Christianized explanation of this power of brooks: when the soldiers led Jesus, they pushed him into the Cebron/Kidron river.
Another group is the so called "Pilate burning". A literal act is when they burn a figurine made of straw, which they name either Pilate of Judas Iscariot. This has some derivatives. Sometimes they beat the strawman before burning. At places a child was chased around the courtyard and if he got caught, he got beaten. At one place the priest hit the step leading to the altar with the Bible, and the congregation beat the benches with sticks. The custom of Pilate burning should be known in other ex-parts of the Habsburg monarchy - Austria, Czechia, Poland, Croatia, etc.
Banishing pests - such as rats or cockroaches - can be done on Good Friday. There are taboos, such as butchering chicken or plowing must not be done on this day. There are places where they light fires, sometimes young men jump over it, in some regions they hold vigils at these fires. It was also customary to treat the day as if someone from the family died, and act accordingly (like dress in black/dark clothing, cover mirrors, etc.)