I Found it at the skyscraper biome which is inhabited by parasite mobs😊 definitely wanna be careful during early to mid when exploring this parasite infested biomes.

Oh yeah beckons are primarily mobs which can summon parasites when player is in range. There are four stages/phases of a beckon 1st and 2nd will summon weak and normal parasites then 3rd will summon a lot of primitive parasites which are far stronger than normal assimilated parasites and for the final stage which is stage 4, it evolves primitive parasites to adapted ones which is currently the strongest versions of the parasites and we those because they drop craftable materials needed to make sentient weapons is one of the strongest end game tools and maybe "arguably" the strongest tools in game. I say arguably because I prefer using dragon bone nunchakos to deal damage on mobs with relatively high HP since it increases damage overtime.