"Dododo" (ドドド Dododo) is an archetype of (mostly) viking-themed EARTH monsters used by Yuma Tsukumo from the Yu-Gi-Oh! ZEXAL anime and manga. All members of this archetype are Warrior monsters, except for the Machine "Dododo Bot".
The effects of the monsters, particularly "Dododo Buster", are designed to allow for easy Rank 4 and 6 Xyz Summons. In addition, they all have respectable ATK and DEF on their own, and two of the five members of the archetype excel at dealing with opposing card effects when they attack; "Dododo Bot" cannot be affected by other cards (allowing it to punch through such defenses as "Dimensional Prison" unhindered), while "Dododo Warrior" negates effects that would activate in the Graveyard such as "Necro Gardna".
"Dododo Witch" allows you to Special Summon other "Dododo" monsters in either face-up Attack Position or face-down Defense Position. The former can be used to bypass the Summoning restrictions of "Dododo Bot", while the latter can be used to effectively Summon the Level 8 "Dododo Swordsman" and use its effects, letting it destroy two face-up monsters, and potentially turning it into a 3500 ATK beatstick.