Tabitha Smith, known primarily as Boom-Boom, is a mutant superhero created by Jim Shooter and Al Milgrom, who first appeared in Secret Wars II #5 (November 1985). Born in Roanoke, Virginia, her powers emerged at age 13, enabling her to generate plasma orbs of varying sizes that explode with concussive force on impact or after a timed delay. Rejected by her divorced parents and subjected to physical abuse from her father upon discovering her abilities, she ran away from home, initially adopting the codename Time Bomb. Her early exploits included a notable encounter with the omnipotent Beyonder, whom she briefly accompanied and befriended, before joining the Vanisher's criminal group, the Fallen Angels, where she assumed the name Boom-Boom.
Betraying the Fallen Angels, Boom-Boom sought refuge with X-Factor, becoming a trainee and later co-founding the X-Terminators with other young mutants during events such as the Inferno demon invasion in New York. She subsequently integrated into the New Mutants, developing a romantic relationship with Cannonball (Sam Guthrie) and refining her power control under the team's guidance. When Cable reorganized the New Mutants into the paramilitary X-Force, she remained a core member, briefly using the codename Boomer while participating in confrontations against threats like the Mutant Liberation Front and Stryfe.
Following personal trauma, including her father's near-fatal encounter with Sebastian Shaw and Holocaust, Tabitha underwent a significant transformation, adopting the codename Meltdown, a more mature appearance, and a volatile personality during her tenure in a covert X-Force led by Pete Wisdom. Later, she joined the unconventional anti-terrorism squad Nextwave, reverting to a playful demeanor and the Boom-Boom identity without a formal codename initially. In more recent arcs, she has contributed to mutant initiatives on Utopia and Krakoa, aided teams like Cable's X-Force, survived anti-mutant purges, and engaged in outreach missions, consistently employing her explosive abilities in defense of her community.