Black Tom was born in Dublin. He is the cousin of Sean Cassidy, the Banshee, a member of the X-Men. He was also once the only friend of the Juggernaut. He has a rivalry with Sean, mainly because Sean won both Cassidy Keep and the family fortune from Tom in a game of dice. They were also rivals for a woman named Maeve Rourke, whom Sean married. While Sean was away, working for INTERPOL, Maeve gave birth to their daughter, Theresa. Not much later, Maeve died in an IRA bombing. With no means to contact Sean, Tom took care of Theresa. When Sean returned to learn of his wife’s death, he was devastated. Before Tom could even tell him of the existence of his daughter, Sean lashed out at Tom with his sonic scream for not having taken better care of Maeve. While Sean flew away in anger, Tom fell into a chasm, breaking his leg as a result of the attack, which left him with a limp. Angrily, Tom swore to make Sean pay and vowed to never tell him about his daughter, raising her himself instead.
Black Tom Cassidy was created by Chris Claremont and Dave Cockrum in 1976 and first appeared in X-Men #99.
Black Tom was originally normal in all aspects, minus being a mutant. His original principle power was that he could generate blasts of heat through a wooden medium, such as the shillelagh that he often carries. After an altercation at the World Trade Center, Black Tom's physiology was altered when a plant substance was grafted into his body to help the healing process. A reaction occurred (despite the use of Deadpool's blood acting as a healing factor) and the plant part of Tom's body soon took over, making Black Tom a complete plant man with plant powers. He was soon driven mad and continued his terrorist ways. After M-Day, however, Tom woke up to old body and his old powers. He had gone full circle.
Major Story Arcs
Tom becomes a criminal and is apprehended. While serving time in prison, Tom meets and befriends the Juggernaut. The two become close friends and allies and work together on their various heist/adventures. As part of his revenge scheme against Sean, Tom murders a lawyer ally of Banshee. Black Tom and Juggernaut then take Banshee and the other X-Men prisoner at Cassidy Keep. He is defeated in a duel by Banshee. Black Tom and Juggernaut next hire Arcade to kill the X-Men.
On a heist in San Francisco with the Juggernaut and Theresa (going by the codename Siryn), Tom encounters and fights the original Spider-Woman, along with several of the X-Men. This conflict ends in Black Tom's temporary capture. While in custody, Black Tom exonerates Theresa of responsibility for her crimes and writes a letter to Sean explaining that she is Sean's daughter. The X-Men bring Theresa back to their headquarters, where she is joyfully united with her father.
Tom next sends the Juggernaut to abduct Madame Web, observing Juggernaut's battle with Spider-Man from afar. Black Tom is briefly endowed with half the powers of Juggernaut by the Ruby of Cyttorak. He teams up with Juggernaut against Spider-Man and the X-Men.
Black Tom next takes Gideon and Sunspot hostage (during Sabotage) on behalf of Arianna Jankos. He uses an inter-dimensional teleporter to return the Juggernaut to Earth. He then battles Siryn and her teammates in X-Force. Cable shoots Black Tom, and Deadpool takes Black Tom to Mr. Tolliver.
After being shot by Cable, Tom is sent to France by Mr. Tolliver's assitant Mr. Foley, where doctors spend months grafting a wood-like substance onto his wounds, healing him and allowing him to channel his bio-blasts directly through his fists. He's picked up by the Juggernaut and the two get involved in the hunt for Tolliver's will.
The first order of business is to gain information. They catch up with Mr. Gezdbadah just after Deadpool saves the man from some mercenaries with the same intentions as Black Tom. Juggernaut takes out a building to stun Deadpool and Black Tom uses his new wooden arm to channel a blast to the back of Deadpool's head. They then interrogate Gezdbadah about a briefcase he holds containing a disc about the will.
With briefcase in hand the two board a commercial plane. Deadpool tracks them and boards the plane. Black Tom sends another blast at Deadpool, who retaliates with an explosive. Black Tom is sucked out the plane and Deadpool catches him with a rope. Black Tom is then used as bait for the Juggernaut to give up the briefcase. Juggernaut doesn't care as much about the will as he does about Black Tom and freely gives the information over. Deadpool then lets Black Tom plummet from the plane. The Juggernaut leaps to the earth after him.
Unfortunately, due to a genetic virus, the plant substance spread over Tom's body, and only the mutated cells of the mercenary Deadpool (due to his healing factor) were able to help Tom stop the spread of the plant growth. This treatment did not last for long. The spreading began anew, to the point where Tom was completely composed of plant matter. As a result, his powers included control and manipulation of all manner of plant life, to the point where he could make plant doppelgangers of himself, or anyone else. He grew insane as a result and, at one point, went after Generation X in an attempt to bring suffering to his brother.
During this time, Black Tom resurfaced as a member of the latest incarnation of the Brotherhood of Evil Mutants. Earlier, Juggernaut had infiltrated the X-Men for him as part of the Brotherhood's plan, though Juggernaut slowly changed during his time with the X-Men, mostly due to the positive influence of the young boy Sammy Paré. Juggernaut rejoined the Brotherhood, secretly planning on turning on them when the time was right. Sammy stumbled upon the group and, assuming that Juggernaut was betraying the X-Men, started lashing out. In retaliation, Tom brutally murdered the boy, causing Juggernaut to attack Cassidy, dismembering him. Due to Tom's new plantlike physiology, this did not hurt him. Juggernaut managed to escape and warn the X-Men, while Black Tom led an attack on the X-Mansion. Besides killing the school's cook, their mission was a failure. In the end, Xorn sucked Black Tom and the rest of the Brotherhood into a black hole.
After M-Day, Black Tom woke up as a human again, losing his secondary mutation but possibly still retaining his old powers, along with his sanity. The organization Black Air hired Tom to attack the new incarnation of Excalibur, of which Juggernaut was now a member. Though he easily defeated the others, Juggernaut confronted his former friend and convinced him to turn himself in for the death of Sammy, saying "He was a kid, Tom. An' you an' me, for all our faults, we used ta be better than that." Tom also showed remorse for killing the child, "That wasn't me, Cain, you know that. I wasn't in my right mind... You've got to understand... that mad life, before... it was like some dream."
Originally, his principal power was Bio-Organic Thermokinetic Blasts, generating concussive blasts of force through any wooden medium. He typically carries a shillelagh, a traditional Irish wooden fighting stick. He is immune to Banshee's sonic powers, and Banshee is immune to his blast power.
Plant Growth: Cassidy could grow to immense size
Healing Factor: regenerate damaged or destroyed body parts with great speed
Chlorokinesis: He could also mentally control all plant life within his vicinity
Planet Consciousness: distribute his consciousness amongst plants he controls
Life-Force Absorption: Cassidy could drain the life force of organic beings
Height: (currently) 6'0"; (formerly) Variable
Weight: (currently) 200 lbs.; (formerly) Variable
Unusual Features: Up until recently, he was made up out of plant matter.
House Of M
In this reality, Tom is a member of the Genoshan Black Ops.
He is a drug dealer here, and he is also shown to have some kind of tie to The Brotherhood.
Black Tom Cassidy appears in X-Men: The Animated Series and is the brother of Banshee. He teamed up with Gladiator and Juggernaut to abduct Lilandra. As the X-Men attempted to save Lilandra, Banshee accompanied them to their castle. He moved to attack the X-Man but Banshee blocked it and said that neither of their powers would be effective against each other. They fought each other fist to fist. Jean Grey, in the form of Phoenix, then appeared and aided the situation.