It's possible you're thinking of:
* "Tiny Titan": A short-lived comic series featuring younger versions of the Teen Titans. While it didn't feature a character named Timmy Tantrum, it did include a few recurring villains like "The Kitten" and "The Wildebeest."
* A fan-made character: It's possible someone has created a fan character with that name, but it's not part of official Teen Titans canon.
Could you provide more context or details about where you heard this name? Perhaps you have a character from another cartoon or comic series in mind, or maybe you misremembered the character's name.