LarpBook has a review of an Aliens larp called “Colony Wars”, in which they mention an interesting technique: puppets!
An aspect to this game that really stood out was the use puppeteering. It worked like this. In game there were creatures (face huggers and giant spiders) that the players encountered. The actions of these were controlled by a puppeteer who wore black. The idea was that players would focus on the beastie and not on the crew member. This worked supremely well. The players role-played keeping their focus on the creatures and ignored the crew. Speaking to them later it looks as if they were genuinely only observing the puppets.
Sadly there’s no photos to see how they looked, or what they used for control. But its a potentially stealable technique.