Flying enemies stick to other monsters and players

In vanilla Heretic and Hexen, flying monsters may encroach into other monsters' hitboxes when moving vertically, causing both monsters to become stuck until one of them is killed. This occurs most frequently in Heretic maps where fire gargoyles are mixed with regular gargoyles or disciples, as they are missing from a hardcoded check intended to prevent flying monsters from moving over or under each other. However, it can more rarely occur with other combinations of creatures in both games, especially when they are near walls.