Happy Halves! (* do not have half in their name)

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Across
  1. 1. sale
  2. 6. *a math teachers Halloween costume, because they're scary (to some)
  3. 8. *animal hybrid when a unicorn esque sea creature is attracted to the vocal and hybrid likely to likely to (whale) sing
  4. 10. *the star ingredient of a (pre allergy concerns) common three letter abbreviation lunch
  5. 12. a source of Harry Potter's adventures
  6. 14. climbing meca in Yosemite
  7. 15. if camels really were to wrestle, this move could also look a bit like yoga (name, minus half, is shared with a renowned anti-apartheid revolutionary)
  8. 18. *mythical Greek creature
  9. 20. *partially striped animal hybrid whose name would be great in scrabble and contains a tool to open doors
Down
  1. 2. *coffee accessory that offers half this macromolecule of heavy cream
  2. 3. (politics) group that advocated in favor of civil service reform and a merit system in the late 1800s. stalwarts vs
  3. 4. astronomically, this phase dne
  4. 5. visual body art on a particular limb
  5. 7. *(usually thought to be) half full, or empty
  6. 9. *crossed animal prized in harsh climates of Tibet and Mongolia
  7. 11. pivot point in the semester when countdown may reasonably commence
  8. 13. P32s decay rate
  9. 16. musical shorthand, resembles a little d
  10. 17. *part of a Sesame Street duo who, at least superficially, shares some lifestyle choices with you
  11. 19. outrageously priced commercials tend to showcase here during the super bowl