So I am having an issue where when I'm a creeper I cant use the ability and so with all the other mobs with the use of R it may just be because I use the R key to drop items but I also tried changing that and it still didn't work? maybe add a keybind

sorry for my English if it was hard to read

nvm i have find the issue i was not using gunpowder sorry

but could u add a way for you to see the player client side when morphed into a mob for example if i was on a server and morphed into a blaze i would see the player (me/the player's skin) and not the blaze model but the other players would still see the blaze i think that would be pretty nice!

Gunpowder/items for abilities is only required on old versions of the mod. Make sure you are using the latest version; there will be an entry in your options page to configure the key if something else is bound to R.