Scuttletide

{1}{U}Enchantment

{1}, Discard a card: Create a 0/3 blue Crab creature token.

Delirium — Crabs you control get +1/+1 as long as there are four or more card types among cards in your graveyard.

The token is named Clue Token and has the artifact subtype Clue. Clue isn't a creature type. (2021-06-18)
You can't sacrifice a Clue to activate its own ability and also to activate another ability that requires sacrificing a Clue (or any artifact) as a cost, such as that of Lonis, Cryptozoologist. (2021-06-18)
The tokens are normal artifacts. For example, one can be sacrificed to activate the ability of Breya's Apprentice and one can be the target of Break Ties. (2021-06-18)
The triggered ability triggers when creatures are declared as attackers attacking you or a planeswalker you control. It will not trigger if an effect puts a creature onto the battlefield attacking you or a planeswalker you control. (2021-06-18)
The card types that can appear in a graveyard are artifact, battle, creature, enchantment, instant, kindred, land, planeswalker, and sorcery. Legendary, basic, and snow are supertypes, not card types; Vedalken and Wizard are subtypes, not card types. (2021-06-18)
Discarding a card is part of the cost of Scuttletide's first ability. There is no time for players to respond to the ability before the discarded card is in the graveyard. (2021-06-18)