Rigellians

Rigellians were an enemy that the player had to tap during the Treehouse of Horror XXV Event. The Rigellians only appeared in a player's town after Pt. 4 of the Free Hugs questline, and after building the Weapon to actually be able to tap and kill them. Once this was done, the Rigellians began to spawn in the players Springfield, and in Neighbor Springfields.

When the Rigellians were tapped on in the player's own Springfield, they yielded three Probes per squish during the first phase of the event (October 7th - October 19th), two Ray Guns per squish during the second phase (October 20th - October 30th) and five Protein Strands per squish during the third phase (October 31st - November 12th). Rigellians also had a small chance at spawning Grem-Alien Eggs, Ammo and Treat Bags. Rigellians spawned in a player's town at a rate of 1 every 5 minutes with a max at 80 Rigellians (50 will be visible, and as they are tapped, the remaining 30 will spawn).

When in friend's towns, the players had a limit of 90 friend Rigellian interactions per day. Each Rigellian squished in a friend's town yielded one of the current currency, but no treat bags, eggs, or ammo. Once the limit was reached for the day, no more Rigellians could be squished until the next day.

If the player purchased the Rigellian Hunting License for 90 Donuts, it increased the amount of currency that the Rigellians yielded in friends's towns from one to two, so if all actions were completed, it doubled the amount of currency the player obtained from friends' towns. This did not affect the amount yielded in their own towns.

Grem-Aliens
Another type of Rigellians were the Grem-Aliens. They could be placed by a player in their friends' towns using Grem-Alien Eggs. Grem-Alien eggs were obtained from tapping Rigellians, or from buying them in the store.

Grem-Aliens could be placed in Neighbor's towns, but could only be tapped in the own player's town. If it was not tapped within four hours of being placed in the player's Springfield the player who place it earned a reward, if it was tapped before the four hours then the reward was shared.

Weapons
The Nails obtained from the Bags could be used to craft the Players weapon. The Weapon was used to squish the Rigellians that swarmed the towns. The higher level of the Weapon, the wider the shockwave radius was from the Rigellian that was tapped, and the shockwave squished any other Rigellians it hit.

After first building the weapon, the Board With a Nail In It quest was unlocked.

Alien Attacks
Rigellians that roamed around player's towns could attack characters who were either doing a visual task or had no task. The aliens took over the character and morphed into the characters likeness. The following characters could be infested.