• His name is an anagram of “Goners”.
• He’s the only character in Undertale to mention the Delta Rune by name.
• He’s a turtle monster and Gaster Blasters look like turtle skulls.
• He fought in the war between Humans and Monsters, so he would’ve been alive to know Gaster.
• He’s aware that shopkeepers can’t be hurt by Frisk, so he has some amount of meta knowledge.
• His son is a priest that worships the Angel, who the Fun Gang are apparently supposed to stop.
I’m not sure what this all could mean (especially since he’s dead in Deltarune) but I think it’s still something worth discussing.
Edit: Just remembered that the Fangamer version of the Tarot Cards replaced Gaster with Gerson.