Forum:Worm dimikles effect

worm dimikles: 1700 atk 1400 def flip: this card gains 300 atk and def

suppose my opponent with 1600 atk attacks my face down dimikles, does he lose 100 life points or does my worm get destoryed? i ask because in tag force 5, everytime my worm dimikles is flipped up, i see no change in def. Then again, I have only seen monsters with 1800 or higher atk attack my face down dimikles.