Ashborn colossus

When Ashborn Colossus enters the battlefield all creatures get -1/-1.
{r}: Ashborn Colossus gets +1/-1 until end of turn.
{b}Ashborn Colossus gets -1/+1 until end of turn.
Born from the smoldering remains of a mountain they roam across the lands reeking havoc upon any civilization they cross.