meaning: change, strange
大変 == taihen == very
変身 == henshin == metamorphosis, disguise, transformation
Bottom radical is 'striking hand/coerce'. Henshall suggests taking the top
radical as a variant of 'red', and the bottom radical as 'sitting crosslegged',
for the mnemonic:
'Change to a sort of red as one sits crosslegged'
...probably not one of his better mnemonics...