A well placed Super Missile can kill an Owtch in one hit, but they can also be killed with powerful beam weaponry, especially when combined with the Charge Beam. It is inefficient to try and attack these creatures with weaker beam weapons, but Power Bombs and the Screw Attack are quite effective.
While haphazard navigators are bound to discover Owtches, careful observers might be able to keep a safe distance and even see the tip of an Owtch’s center spike poking through the ground when they are in momentary hiding.