Gift of Chaos
A Chaos Sorcerer may use this psychic power in the Shooting phase instead of shooting. The Sorcerer may be in close combat at the time as may the target. Pick an enemy model or a friendly model within 2" of the Sorcerer and then take a Psychic test in order to use the power. If the test is successful, roll a D6. If you roll over the victim's Toughness (use the base Toughness, not the modified Toughness for being on a bike for example), or you roll a 6 no matter what the victim's Toughness is, then the victim is transformed into a Chaos Spawn, with no armour save allowed (invulnerable saves may be taken as normal). If no Chaos Spawn model is available to replace the model transformed then just remove it as a casualty.
See the Daemon Spawn wargear entry for the Chaos Spawn profile. The new Chaos Spawn will form a unit with the Sorcerer who transformed him. They are counted as being part of the Chaos army from the moment they are transformed and may attack in that Assault phase, as long as they have not already done so. Models turned into Chaos Spawn are treated as having been killed for Victory point purposes, even if the Spawn survives the battle. The only friendly models that may be transformed are Chaos Space Marines (of any type), not followers.
Errata — Chapter Approved: Codex: Chaos Space Marines Q&A (v3.0): Gift of Chaos does not ignore Invulnerable saves. If cast through a Warp Focus and the resulting Chaos Spawn would be more than 2" from the Sorcerer, simply move the Spawn into coherency with him — the newly-formed bubbling mass flows to its new master before reforming.