Second Forms were a term used to refer to Threat-created forms for The Threat's Top 10, first debuting in Fantendo Smash Bros. Victory. They were newly "unlocked" forms on par with Hyper Mode forms, drastically altering the user of the form's appearance and enhancing their skill set. Currently Quartz is the only canon user of the Second Form, although Second Forms appear in non-canon games like Fantendoverse X: Space as What-Ifs?.
Second Forms first debuted during the events of Fantendo Smash Bros. Victory's story mode Days of Victory. Quartz appeared before The Threat, asking her for the ability to sire children, of which The Threat would only agree to her demands should she defeat Former Four in battle. After defeating Former Four, The Threat created Quartz's Second Form, although this appeared to have the side-effect of making Quartz attack Unten whenever she got close to him, beyond her control.
Second Forms are on scale in terms of power with Hyper Mode forms, and can be unlocked by the user at will, although they cannot willingly revert themselves, either needing to be tired out enough or knocked out by a opponent to revert back. Most Hyper Forms seem to grant the user their greatest desire, but at a heavy cost to their self-control. For example, Quartz's Second Form gave her the ability to sire children, but it also gave her the uncontrollable urge to kill anyone she was attracted to.
Quartz's Second Form appears as her Finisher move, giving her a expanded moveset with several new and enhanced abilities. It also appears a major plot point in Days of Victory, as Quartz battles and defeats Former Four for the form, although she finds that it has a drawback that she was not informed about. Knowing that she may never be able to love Unten the way she wants to, she sets off on her own journey of self-discovery following Days of Victory.
A alternate version of Grendel appears with a Second Form, giving him vast power at the cost of insatiable hunger, which turned his biggest leverage against the other Top 10 members against him, as they now have turned against him, knowing he can no longer control his hunger. Additionally, a alternate version of Sakeena Kamel with a Second Form appears, giving her vast defensive options and the ability to create clones of herself at the cost of her humanity and emotions.
- The Second Form was originally exclusive to Quartz, which was a reference to one of her design inspirations, Frieza. This changed with the introduction of Second Form Grendel in Fantendoverse X: Space.
- Grendel's Second Form has his mandibles take on a new texture resembling the Dragon Ball character Cell.
- Sakeena's Second Form has her gain metal armor around her entire body as well as a tail, resembling the Dragon Ball character Meta Cooler.
- Makara's Second Form is unusual in that it references two things: the Dragon Ball character Hirudegarn and Gigan from the Godzilla franchise. This came from their creator Ambrisynth (t∣b∣c) suggesting that Makara's Second Form be based off a Kaiju.