User blog comment:Xilinoc/Ch. 655 - THE MIRACLE/@comment-1268838-20151210201730/@comment-5657895-20151210224559

One of the theories going around based off of the raws is that Gerard can make trade-offs. Like turn pain and damage into size and power. And can maybe make other 'Miracles' occur with a similar trade-off. Apparently it's because 'conversion' was highlighted in the original raws. At least, according to some people. So his powers might be more versatile than we think.