Re-fluffing a Barbarian for first-time player

[JLandan]

I would suggest the Path of Wild Magic. The Wild Surges cartoon up nicely (is cartoon a verb?). Path of the Circus or Path of the Clown.

Shadowy tendrils can be colorful streamers and do radiant damage instead.
Teleport is the same but makes a popping noise.
Intangible spirit could be a balloon or miniature clown. I once played a halfling farmer barbarian that made chickens.
Magic infused weapon could be cartoonishly big or balloon formed.
Retribution damage could be from a waldo or an extending cartoon fist, but still force damage.
The multicolored protective lights needs no change.
Flowers and vines needs no change.
The bolt of light can be prismatic like a rainbow but otherwise needs no change.

Bolstering Magic can be handing over a balloon or flower that pops granting the bonus.

Unstable Backlash and Controlled Surge use Wild Surge, so no further change is needed.

PS... The witchlight carnival hand background might be fun with this.