As soon as Sans Undertale Spawns, he will run offscreen. A circle of bone spikes will surround all players in the arena. Horizontally moving spikes(perpendicular to north/south) will start spawning in an attempt to hit the player. If players manage to survive the first wave, 3 more will spawn with increasing difficulty.
- The Second wave will still be the horizontal spikes. - The Third wave introduces vertically moving spikes, forming a grid-like pattern to the already limited movement area - The forth and last wave. Spinning shapes made out of spikes will spawn along with the vertical and horizontal spikes.
Once all waves are done, sans will take a short break, taking back all spikes, leaving space for attack.
Once his HP is down to only 9999, he will start using Gaster Blasters(Laser Cannons that made their debut in Unal Tered), whose will target the player and fire at rapid succession.
When defeated, sans will drop Nothing and fucking die. Hard-Mode is unlocked after that.
- Sans Undertale fucked your mom.
- Sans Undertale is anagram of Sans Deltarune. Wheter this was intended from the developers or a mere coincidence is unknown.
- During the forth wave of his initial attack pattern, if players do manage to exit their spike arena before they are intended to, they can catch sans dabbing on them in his hiding spot.
- The word Sans is a portmanteau of Saint and Fans.