ITT: Pokemon's Evolution mechanic

[Toffee.]

[spoiler=Cradles]
True Fossil - Sprout Cradle
EARTH / Level 4
[Plant/Effect]
When this card is Normal Summoned: You can add to your Hand 1 "True Fossil - Weep Cradle" from your Deck. If this card is destroyed by your Opponent's card(either by battle or card effect), you can pay 1000 Life Points: Special Summon this card from the Graveyard during that turn's End Phase.
ATK / 800 DEF / 500

True Fossil - Weep Cradle
EARTH / Level 8
[Plant/1st Stack]
If this card is destroyed by your Opponent's card(either by battle or card effect): Draw 1 card. You can Normal Summon this card by placing it on top of a "True Fossil - Sprout Cradle" you control. As long as "True Fossil - Sprout Cradle" is under this card, this card gains the following effect:
•Each time this card destroys an Opponent's monster as a result of battle, add to your hand 1 1st Stack or 2nd Stack monster from your Deck to your Hand. Then, inflict 800 damage to your Opponent.
ATK / 2200 DEF / 2300

True Fossil - Life Cradle
EARTH / Level 12
[Plant/2nd Stack]
If this card is destroyed by your Opponent's card(either by battle or card effect): Draw 1 card. You can Normal Summon this card by placing it on top of a "True Fossil - Weep Cradle" you control. As long as "True Fossil - Weep Cradle" is under this card, this card gains the following effect:
When this card is Summoned, You can Target 1 1st Stack monster in your Graveyard: Special Summon it. Then, place 1 2nd Stack monster of the same type as the Summoned monster, on top of the Summoned monster(from your Deck). This card cannot attack the turn you activated this effect.
ATK / 2700 DEF / 2800[/spoiler]
[spoiler=Shells]
True Fossil - Stepping Shell
WATER / Level 4
[Reptile/Effect]
When this card is Normal Summoned: You can add to your Hand 1 "True Fossil - Surface Shell" from your Deck. If this card is selected as an attack target, you can change it to Defense Position.
ATK / 1000 DEF / 2000

True Fossil - Surface Shell
WATER / Level 8
[Reptile/1st Stack]
Once per turn this card cannot be destroyed as a result of battle. You can Normal Summon this card by placing it on top of a "True Fossil - Stepping Shell" you control. As long as "True Fossil - Stepping Shell" is under this card, this card gains the following effect:
•Once per turn, during either player's turn, you can Send 1 card from your Hand to the Graveyard: Until the End Phase, This card cannot be destroyed by card effects that do not Target.
ATK / 1800 DEF / 2600

True Fossil - Island Shell
WATER / Level 12
[Reptile/2nd Stack]
This card cannot be destroyed as a result of battle. You can Normal Summon this card by placing it on top of a "True Fossil - Surface Shell" you control. As long as "True Fossil - Surface Shell" is under this card, this card gains the following effect:
•Once per turn, during either player's turn, you can Send 1 card from your Hand to the Graveyard: Until the End Phase, This card is unaffected by other card effects.
ATK / 2200 DEF / 3500[/spoiler]

Revival Method
Spell
Pay 1000 Life Points. Activate 1 of these:
•Place 1 1st Stack Monster from your Hand on top of a "True Fossil" monster you control of the same Type.
•Place 1 2nd Stack Monster from your Hand on top of a "True Fossil" monster you control of the same Type.
You can only activate 1 "Revival Method" per turn.