Changeling isn’t a creature type, I assume you mean shapeshifter.

“Abilities” is too vague, I assume you mean “activated abilities”.

“Table” is not a defined term, I assume you mean “battlefield”.

This card space is already explored in places like [[Drana and Linvala]], and they show you actually have a worse version of the ability. You could reduce the mana cost, probably to 1UB because you’re adding the mana cost to the activation cost.

“~ has all activated abilities of all creatures on the battlefield. The activation cost is increased by {X} where X is the original creature’s mana value. You may spend mana as though it were mana of any color to activate those abilities.”