how bout swallowing someone gives them the standard neutral special like always, but the other specials are altered slightly.
like if kirby swallows mario, he will get the fire ball as an n-special, but his up special will have a coin effect, his down special could make a small splash, his side special could turn people around
and kirby ---> samus, n special stays the same, up b, kirby adds screw attack to the up portion of his final cutter, side b, hammer explodes on impact, down b, rock explodes on impact
kirby---> yoshi, n-special " " ", up b launches an egg, down b, has little stars that pop out when he hits the ground, side b, hammer turns into an egg and explodes on impact,
kirby---> lil mac: yadaydyayd.... up b, kirby spins in the z axis while going up, side b, kirby launches forward while swinging hammer, down b, if someone hits the rock, rock shatters causing fragmentation damage.
kirby---> fox: n special..... up b: kirby is set on fire, side b, hammer has invincibility frames, down b, rock has reflector status
kirby---> zss, up b is not much different, side b, adds a plasma whip explosion effect to hammer, down b, rock flips forward,
kirby ---> bowser, up b, kirby spins in z-axis, side b, hammer grabs opponent and slams them into the ground, down b, not much different
kirby---> villager, up b, adds balloons that makes kirby reach higher, side b, explodes on impact, down b, plants a tree
kirby--->lucario, up b, adds a small aura around kirby, side b, hammer adds forcepalm effect, down b, another rock appears out of no where and flies from the opposite side of atacker
*by now im getting ridiculous and this will never happen, but i hope you get the idea,*