If Hot Feet spot player-characters they will come hopping and start attack (except for worlds set to "peaceful") with hits and quite often also with burning-attacks that last for ca. 2 seconds and do heavy damage. However since Hot Feet usually hit again rather fast and can inflict fire damage again quickly, they can be quite dangerous. Additional to that the Lava layer itself can also inflict fire damage when the heat-scale has fully turned red.