This puzzle was inspired by by Derek Kisman’s fractal word search, In the Details, which contains a crypto word search as one of the steps.
First we solve clues, noticing that the answers are in alphabetical order:
| It ends your sleep (5) | ALARM |
| A feeling of unease (7) | ANXIETY |
| The end of the world, as brought about by horsemen (10) | APOCALYPSE |
| Fear of water (10) | AQUAPHOBIA |
| Insects in the stomach when scared (11) | BUTTERFLIES |
| It conquered fear and crossed the road (7) | CHICKEN |
| This word describes Sunday in a Hungarian song (6) | GLOOMY |
| Shuddering fear (6) | HORROR |
| A deviation in signal pulses (6) | JITTER |
| Sad feeling of singles (10) | LONELINESS |
| A moaning ghost living in a bathroom (6) | MYRTLE |
| Adjective describing a fallacy attributing human emotion to nature (8) | PATHETIC |
| His glass is half empty (9) | PESSIMIST |
| Overachiever’s concern (6) | STRESS |
| Type of denial of service attack (8) | TEARDROP |
| Hamlet or Macbeth (7) | TRAGEDY |
| Earthquake harbinger (6) | TREMOR |
| Calming root (8) | VALERIAN |
| Word to describe a baby or siren (7) | WAILING |
| Shed tears (4) | WEEP |
| Producer of wrinkles (5) | WORRY |
| Scary undead (6) | ZOMBIE |
Looking at the word search table, one might notice that the letter frequencies are off, and overall it looks encrypted. We try a substitution cypher. A good place to start is the word PESSIMIST, as the string XXY?YX can be found only in one place. After we place PESSIMIST, it is easy to place STRESS, LONELINESS, and APOCALYPSE. After that the table can be deciphered.
| A | V | M | Y | R | T | L | E | W | E | E | P | E |
| C | E | N | E | R | R | E | A | L | I | Y | E | S |
| I | C | T | E | A | R | D | R | O | P | D | S | P |
| T | N | H | A | F | Z | O | M | B | I | E | S | Y |
| E | Y | S | I | Q | E | C | W | T | N | G | I | L |
| H | M | S | I | C | U | A | V | I | O | A | M | A |
| T | O | E | N | C | K | A | L | A | L | R | I | C |
| A | O | R | L | E | L | E | P | A | D | T | S | O |
| P | L | T | R | E | N | T | N | H | R | H | T | P |
| E | G | S | R | O | M | E | R | T | O | M | C | A |
| S | E | I | L | F | R | E | T | T | U | B | L | A |
| W | A | I | L | I | N | G | R | E | T | T | I | J |
| N | P | N | I | N | E | Y | T | E | I | X | N | A |
Extra letters (in yellow) spell A VENEREAL INFECTION CALLED THE CLAP NINE. This clues GONORRHEA. The last step is to encrypt GONORRHEA using the same substitution cipher. The answer is NECESSARY.