Crossword Clue:

FOSSILIZE to turn into a fossil

AnswerCrossword Clue
OVERUSETurn into a chestnut
MAKETurn into a success
SPOILTurn into a brat?
TWISTTurn into a pretzel
CRUSADEWhat a cause might turn into
EXTRACREDITIt might turn a B into an A