monster rodio

with this feat you can gain advantage to leap onto a monster that is large or larger's back, while you are up there all your attacks are at point blank but you can still roll to try to get a nat 20,but 1 is still fumble. Every round the monster can use its turn to try to shake you off it's a DC10 STR save to stay on but the DC goes up 5 for every size category larger the monster is above large.