1A - FIAT - T + S + CO ("crushing" is an "abber") / 4A - TR ("truncated tree") + ENDS ("stops") / 5A - STAT ("info") + I + C / 1D - ET ("Alien) inserted into ("invading") FISH ("hamlet") / 2D - A SPEAR anagrammed ("Absurd") / 3D - CAD ("rake") + DIE ("perish"), with "and become" linking