Keyword: Convert

Underdark Beholder enters the battlefield with ten eyestalk counters on it.
If Underdark Beholder would be dealt damage, remove that many eyestalk counters from it instead. If you can’t, sacrifice it.
Whenever Underdark Beholder attacks, reveal cards from the top of your library until you reveal an instant, sorcery, or enchantment card with converted mana cost less than the number of eyestalk counters on Underdark Beholder. You may cast it without paying its mana cost. Shuffle your library.

Spark (Activate spark abilities by spending or giving yourself spark counters. Activate only one spark ability per turn, and only as a sorcery.)
+1: Blood Poet gains lifelink until end of turn.
−3: Target opponent discards a card. You gain life equal to its converted mana cost.

Flash
Enchant instant or sorcery spell on the stack
When Animate Spell becomes attached to an instant or sorcery, put that card onto the battlefield under its owner’s control. It’s a creature in addition to its other types with power and toughness each equal to its converted mana cost.
When Animate Spell leaves the battlefield, enchanted card’s owner sacrifices it unless they cast it.

Underdark Beholder enters the battlefield with ten eyestalk counters on it.
If Underdark Beholder would be dealt damage, remove that many eyestalk counters from it instead. If you can’t, sacrifice it.
Whenever Underdark Beholder attacks, reveal cards from the top of your library until you reveal an instant, sorcery, or enchantment card with converted mana cost less than the number of eyestalk counters on Underdark Beholder. You may cast it without paying its mana cost. Shuffle your library.

Flash
Enchant instant or sorcery spell on the stack
When Animate Spell becomes attached to an instant or sorcery, put that card onto the battlefield under its owner’s control. It’s a creature in addition to its other types with power and toughness each equal to its converted mana cost.
When Animate Spell leaves the battlefield, enchanted card’s owner sacrifices it unless they cast it.

Spark (Activate spark abilities by spending or giving yourself spark counters. Activate only one spark ability per turn, and only as a sorcery.)
+1: Blood Poet gains lifelink until end of turn.
−3: Target opponent discards a card. You gain life equal to its converted mana cost.

At the beginning of your upkeep, destroy another nonland permanent chosen at random, then put a number of +1/+1 counters on Yule Ooze equal to that permanent’s converted mana cost.
, Eat some food: Regenerate Yule Ooze.