Outside of his standard bones, teleportation and telekenesis, Sans still has his Gaster Blasters, however, they’re useless in their normal form and he only has two. Only when they equip onto one or both of Sans’ arms is when their true potential is released, and his iconic left eye changes accordingly. Sans’ Gaster Blasters have two modes: Long-range and Close-range.
Long range comes in one form: an arm cannon. In this mode, his eye changes into a crosshair shape and the cannon can either fire in short little rounds, a small beam (as displayed) and a bigger beam. If they’re equipped onto both arms, then Sans can fire a super charged buster beam when combined. However, that will take a lot out of him, not to mention the recoil is a quite the killer.
As for close range, it comes in one of two forms: claws or an arm blade. His eye turns into what appears to be two sickles opposing each other. The claws can be on one or both arms, but the regular sword can only on one arm. However, like the combined cannon form, Sans can create a large beam sword, but also like the large killer beam, that will take a lot out of him.
Sans can have both activated. By that, I mean he CAN have a cannon on one arm and a blade/claw on the other (Omnimon, anyone?). The downside to that is that he can’t be able to do either of the super beam or sword, since that requires both arms to have the same mode. His eye obviously becomes a mix between the two modes.
The Gaster Blasters DO have a default form, but…they’re more useful as pets in that particular state (and maybe for transportation). Don’t worry, I have a ref for them, too:
Design-wise, they’re just regular blasters with markings on them lol At least it’ll be useful as a color ref.
Also, I personally like the crosshair eye better lol