Boosting Elixir is a rare spell card that gives strength to two friendly units. The strength given to can be increased when leveled up. Boosting Elixir is versatile can fit into any kind of deck.
Similarly to Potion of Growth, Boosting Elixir can fill many of the same purposes it serves.
Since Boosting Elixir can affect one or two units, it gains the most value when you have a pair of units to target.
Cheap units such as Lawless Herd and Green Prototypes are great targets for Boosting Elixir. In fact, decks with low average costs are best for this card, as it will be hard to play efficiently otherwise.
You can control the targeting of the unit by casting it on different units. The effect is identical for both targets, so try to minimize the risk of Boosting Elixir hitting the wrong target.
Note that at level 3 and below, positioning is trickier - be careful to make sure units are going to be bordering before using.
Give 3 strength…bordering…
Give 4 strength…bordering…
Give 5 strength…bordering…
Give 5 strength…surrounding…
Give 6 strength…surrounding…
August 10, 2017: Decreased mana by 1
August 30, 2017: Increased cost and ability by 1
January 31, 2018: Ability requires bordering at lower levels, decreased strength at higher levels