Oh, let me rework it then:
End Game Boss:
X mana 1/1
Whenever this minion enters play, activate a phase based on how much mana has been spent.
Each time someone has to check the rulebook for phases, they are set to 1hp (including you).
Phases
1 mana
At the beggining of your turn, this and another random minion (anywhere)gains +1/+1.
2 mana
Gain +1/1. Discard a random card from all players hand and deal damage to them equal to the cost.
3 mana
Gain +2/+2.At the beginning of your turn deal 1 damage to EVERYTHING.
4 mana
Gain +3/+3.Deal 2 damage all minions then 10 to a RANDOM character(player or minion, ANY).
5 mana
Get +4/+4.Destroy any 3 random minions. Deal damage to any player that gets salty
6 mana
Gain +5/+5. Draw 2 cards. Discard the deck.
7 mana
Gain +7/+7. ALL minions are now 1/1.
8 mana
Gain +7/+7.Whenever you Mana leak, remove 1 mana next turn and gain +1/+1 for each mana removed.
9 mana
Gain +8/+8. Add “Road Roller” to your hand(9 mana.Crush all minions, removing them from game.)
10 mana
Gain +9/+9. In 3 turns. Player with highest health loses.

