Team Onslaught was a level editing team active in 1997-1998 and formed by Tom "Mystican" Robinson, Luke "Spike" Cama, Simon "Fraggle" Howard, and Vincent "Vicious Killer" Fong. Justin "DOMiNiON" Saunders also joined for a brief time, contributing a level to Decamatch II: Annihilation.
The formation of the team was inspired by TeamTNT, especially TNT: Evilution. Tom, Luke, and Simon were schoolmates, and Luke met Vincent online. The team intended to develop for several games; because of this, Duke Nukem appeared alongside the Doomguy in the logo, and the website also contained a Quake ranger. Ultimately, however, the only releases by the team were Doom-related.
The main releases by the team were Decamatch and Decamatch II: Annihilation, two sets of ten deathmatch levels. Eternal Khaos, another set of ten deathmatch levels developed exclusively by Vincent, was loosely connected with the team, being available from the website. Simon also developed the Doom launcher program Onslaunch. After Team Onslaught dissolved, various members of the team contributed to the 18 level deathmatch megawad Execution DM, which was lead by Vincent and released in 2000.