This was part of an anthology of stories.
An astronaut appears on a desolated planet. He encounters alien life which is hostile and at one point takes a companion as hostage by removing all their bones and dragging them around.
There’s a standoff where the astronauts threatens to call a code 5 of something, but his superiors tell him not to. The aliens aren’t scared, having a fleet of billions and have taken over other planets easily.
In the end the code 5 is summoned and seemingly unbeatable alien fleet is beaten.