Electric fence

''A beefed up version of the standard farmers electric fence. It ticks at a much faster rate and discharges lethal amounts of electricity. Super-fine and sometimes difficult to see, they're immpossible to hit with grenades.''

In game description

The Electric fence is one of the obstacles faced in the game Hyoogle. As the discriptions says they can not be hit by grenades and can be missed by the untrained eye. If Hyoogle toughs it he will be killed by the electicity and you will have to respawn