Mr. Toaster was made during a thaumaturgic spell going wrong in the Junkyard of waterfalls. Someone had thrown away their toaster, and the spell happened to hit them. Alphys was there, and witnessed the whole procedure. She was afraid that Mr. Toaster and MTT would either fight or get… too comfy with each other, thus she agreed to let H. Fish, Mask, and P. Fish have them