From the Super Mario Wiki
Boomerang Bros. are enemies found in the Beanbean Kingdom in the game Mario & Luigi: Superstar Saga. Completely unlike any other Boomerang Bro., they are extremely tall and thin, wear sunglasses, and have sprouts growing from their heads. Like Troopeas are to Koopa Troopas, this species is the Beanbean Kingdom equivalent of normal Boomerang Bros., with which they share a name in some languages (although Italian and French are both different).
In Mario & Luigi: Superstar Saga, they only inhabit the Gwarhar Lagoon. In battle, Boomerang Bros. throw brown boomerangs, which Mario and Luigi could dodge with jumps. Before throwing, its sunglasses will twinkle; if the right side of the glasses twinkle, it will attack Mario, and if the left side twinkles, it will target Luigi. If the boomerang is dodged on its first pass, it circles around offscreen and Mario or Luigi has to jump over it again as it returns to the Boomerang Bro. that threw it.
Names in Other Languages
||Pun on "boomerang".
||Pun on "Boomerang" and fratelli ("brothers")