gas ---> invisible

invisible -> ghost

secret -> telling (just came into my head, I'm actually rather good at keeping secrets).

telling ----> story

meeting -> greeting

card -> paper

card ----> poker

poker -> chips

chips ---> potato

potato -> skin

skin ---> nude

naughty -> nice

nice ---> good

bad ---> evil

axis ---> line

queue -> wait

service ---> maintenance

maintenance -> repairs

repairs -> broken