“Uninvited” is episode five of season ten of Stargate SG-1.
General Landry has invited the team to Jack O’Neill’s cabin (Jack himself doesn’t appear in this episode though) to spend some time together outside of work. Daniel is still not present, as he’s chasing clues on Merlin’s anti-Ascended being weapon. Sam is in charge of the SGC as there are problems on another world, which also keep Teal’c and Vala occupied, so only Mitchell makes it.
There’s some sort of monster attacking people on a planet one of the SG teams are observing, one where no creatures of this type have been seen before. After killing it, something similar happens on another planet. The only commonality is that there is another team observing there too.
Something is also doing something similar near Landry and Mitchell’s cabin. The various things are, unsurprisingly, connected.