This is a guide for the Legends of Runeterra lab, "Heimer's Madness". It includes the special rules for this game mode, an overview of the premade decks, and a strategy guide.

The Rules

Heimer's Madness is a 1v1 PvP lab that uses randomly generated decks.

[quote from="Lab Description" class="riot"]

It's chaos in the Lab! The Mana Generator's offline and the Cost Reducer's gone haywire. Choose the right cards to add to your increasingly-discounted deck and defeat your opponent in the name of science!

• Start with a shallow deck of random cards and 4 mana
• Instead of gaining mana, each round every card in your hand and deck has its cost reduced by 1 (to a minimum of 1).
• Every round, one player gets to use Heimerdinger's Duplicator: choose one of 4 random cards. Add one copy of that card to your hand, and two copies to your deck!

[/quote]

Notes

• Heimerdinger's Duplicator is a fleeting zero-cost burst-speed spell. You will receive it at the start of the round if it's your attack round.
• The cost reduction applies to cards in hand, in deck, and future offerings of Heimerdinger's Duplicator. In other words: if you are offered a [runecard]Gangplank[/runecard] after Round 5, it will already cost 1 mana -- you don't have to wait additional rounds to reduce its cost.
  • Cards that are generated (e.g., dragons from [runecard]Egghead Researcher[/runecard]) and that are Recalled don't have this immediate discount. Their mana cost is reset to the original amount, but once in hand they will receive the reduction in future rounds.
  • If you have a champion in-hand that is a duplicate of a champion on-board, the discount will be applied to its signature spell. It is possible for signature spells to cost 0 mana.
• The cards you are offered will be from the same regions as your deck. You can be offered followers, spells, and even champions.
• Anything that would increases your mana count in constructed ([runecard]Wolfrider[/runecard], [runecard]Catalyst of Aeons[/runecard], etc) will have the same effect here.

Decks

The decks are randomly assigned and will be of 2 regions. Each deck starts with 16 cards (starting hand of 4, a draw of 1, and a remaining deck of 11). Since you are normally putting 2 cards into your deck every other turn, your deck will stay at 10-11 total cards for the entire game barring any additional card draws or effects like [runecard]Counterfeit Copies[/runecard] and [runecard]Avarosan Trapper[/runecard].

Strategy

When it's your attack round, it's almost always best to use Heimerdinger's Duplicator immediately to see if it changes your attack plans. Exceptions include if you want to trigger a Daybreak effect and if you're so far ahead that you'd rather react to your opponent than optimize your attack.

In general, you'll want to favor mid-sized cards -- i.e., cards that cost between 4 and 7 mana. These cards will be discounted to the 1-3 cost range fairly quickly, allowing you to play multiple each turn and create some crazy tempo. A card like [runecard]Will of Ionia[/runecard], which is generally thought to be too expensive for constructed play, becomes backbreaking when it only costs 1-3 mana. Don't pass up on late-game bombs like [runecard]Brightsteel Formation[/runecard] and [runecard]Warmother's Call[/runecard], though, as they can decide the game and never know when you'll get another offering.

Late game, most cards will cost 1 mana so you should have no problem emptying your hand. This makes card draw especially valuable in this game mode.