ands for a few seconds, then looked over the fingers at the two
of them.

"I've been living in a nightmare for the last week," he said in a taut
small voice, "knowing the thing had come alive and trying to pretend
to myself that it hadn't. Knowing it was taking charge of me more and
more. Having it whisper in my ear, over and over again, in a cracked
little rhyme that I could only hear every hundredth time, 'Day by day,
in every way, you're learning to listen ... and _obey_. Day by day--'"

His voice started to go high. He pulled it down and continued harshly,
"I ditched it this morning when I showered. It let me break contact to
do that. It must have figured it had complete control of me, mounted
or dismounted. I think it's telepathic, and then it did some, well,
rather unpleasant things to me late last night. But I pulled together
my fears and my will and I ran for it. The slidewalks were chaos. The
Mark 6 ticklers showed some purpose, though I couldn't tell you what,
but as far as I could see the Mark 3s and 4s were just cootching their
mounts to death--Chinese feather torture. Giggling, gasping, choking
... gales of mirth. People are dying of laughter ... ticklers!... the
irony of it! It was the complete lack of order and sanity and that let
me get topside. There were things I saw--" Once again his voice went
shrill. He clapped his hand to his mouth and rocked back and forth on
the couch.

Gusterson gently but firmly laid a hand on his good shoulder.
"Steady," he said. "Here, swallow this."

Fay shoved aside the short brown drink. "We've got to stop them," he
cried. "Mobilize the topsiders--contact the wilderness patrols and
manned satellites--pour ether in the tunnel airpumps--invent and
crash-manufacture missiles that will home on ticklers without harming
humans--SOS Mars and Venus--dope the shelter water supply--do
something! Gussy, you don't realize what people are going through down
there every second."

"I think they're experiencing the ultimate in outer-directedness,"
Gusterson said gruffly.

"Have you no heart?" Fay demanded. His eyes widened, as if he were
seeing Gusterson for the first time. Then, accusingly, pointing a
shaking finger: "_You invented the tickler, George Gusterson! It's all
your fault! You've got to do something about it!_"

Before Gusterson could retort to that, or begin to think of a reply,
or even assimilate the full enormity of Fay's statement, he was
grabbed from behind and fr