Summer Beast (夏の獣 Natsu no Kemono) is a special super-powered boss only found in Co-op Mode. She was originally introduced during the Summer Games event in Version 2.2.
Passives
- (Unlisted) Start the game with 0 stars and 10 lives.
- (Unlisted) Use
Hype Mode at the beginning of the game. - At the start of Boss turn, summon a Minion (up to a maximum of Boss Lvl).
- When a Seagull Minion is defeated, lose 1 Hype.
- When a player suffers KO, gain 1 Hype.
- (Below Hyper Difficulty) At the start of Boss turn, if Boss has 10+ Hype, use Rampage.
- (Hyper Difficulty) At the start of Boss turn, if Boss has 10+ Hype, use Rampage (hyper difficulty).
Overview
Summer Beast is a unique boss as she comes with various mechanics that differs her from most other bosses.
- "Setup" mechanic - gain Hype and turn them into Rampage once she has 10+ Hype.
- Summon minions - much like , Summer Beast can spawn Seagull minions to fight for her.
- Extra lives - she may be low on HP, but she makes up for having 10 lives.
Strategy
Summer Beast has a "setup" mechanic based on gaining Hype. While it's possible to control her Hype count by KO'ing her Seagull minions and staying alive, the player will inevitably have to face one or two 
Rampage because there are too many ways for Summer Beast to gain Hype. Rampage will damage all players and the more times Summer Beast uses it, the more damage it can inflict. On top of that, Summer Beast can potentially challenge multiple players after each Rampage, dealing even more damage to the players thanks to the movement buff and her innate +2 ATK from 
Hype Mode. To lower the damage taken during and after Rampage, as well as most cards that either enhance Summer Beast and/or her minions (
Play With Birds, 
Play Tag, 
Watermelon Splitting, 
Hype It Up), or deal out-of-battle damage (
Birds, 
Splash Water, 
Sandwich Thieves), defensive battle cards, healing cards, and cards that can reduce/negate the damage should be a high priority.
Summer Beast can spawn Seagull minions. Unlike the minions from Big the Haruo or , these Seagull minions will always challenge any player they pass through, giving them a chance to deal significant damage and posing a potential threat to fragile characters. To deal with this, Avengers can be a wise choice to repel them with proper support from other teammates. 
Pet Snacks can also be considered for its cheap cost, low level, and a stackable effect that reduces their strength quite well. Unfortunately, KO'ing these Seagull minions doesn't really help much against Summer Beast herself as she usually summons them at a faster rate, but they can be used to obtain wins for norma. The swarm of Seagull minions can make 
Seagull Master quite problematic, it's advisable to pack 
Star-Blasting Light in the deck, as it not only removes all the 
Dance of the Seagulls traps, but also damages Summer Beast and her Seagull minions, even if just by a small amount.
Summer Beast's extra lives makes her somewhat similar to — she will never take more than 5 damage in a single life most of the time, as she only can have 5 HP if not considering the extra HP from Rampage and Dance of the Seagulls, the players should aim to deal just enough damage to KO her instead of overkilling. Summer Beast will skip her current card if she gets KO'd before her turn, so it is possible to forcefully skip her cards with a direct KO. The lives mechanic also makes her one of the few co-op enemies affected by 
Forced Revival, which will revive Summer Beast with 3 HP if used before her turn, allowing the players to deny a full HP heal. And because of her low HP, as Dealer can be extremely helpful with her 
Miracle Red Bean Ice Cream — by dealing it to other Attackers/Avengers on the team, they can reach insanely high ATK and might be able to consistently KO or significantly damage Summer Beast in 1 hit.
Summary
- Every chapter, a will spawn on Summer Beast's panel, up to her level.
- In Battle, she will gain +2 ATK and +1 DEF.
- Whenever she suffers KO, she will recover on her next turn. She has 10 lives which are depleted as she is KO'd.
- Any time a player dies, she will gain Hype. If any of the Minions is killed, she will lose Hype.
- When Hype reaches 10, she will damage all players, roll 2 dice, won't stop moving after fighting a player, and will gain Boss Level x 1 HP for her current life. On Hyper Mode, she will also gain +1 ATK permanently.
- Home panels disappear on Chapter 40.
- More Boss panels every 2 chapters with the Terror field Event.
- All panels except Warp and Warp Move will become Boss panels by Chapter 40.
Update History
V3.16
- Updated Watermelon Splitting description.
- Old description: "Until the end of its turn, Boss will gain +5 ATK and won't stop when challenging a player. For each KO'd player, gain 2 Hype."
- New description: "Until the end of its turn, Boss will gain +5 ATK and won't stop when challenging an enemy. For each KO'd player, gain 2 Hype."
- Updated Rampage description.
- Old description: "Lower Hype to 0. All players take 1 damage for each stack of Rampage. This turn, roll 2x for move and don't stop when challenging a player. Gain Boss Lvl x 1 HP."
- New description: "Lower Hype to 0. All players take 1 damage for each stack of Rampage. This turn, roll 2x for move and don't stop when challenging an enemy. Gain Boss Lvl x 1 HP."
- Updated Rampage description of the Hyper difficulty variation.
- Old description: "Lower Hype to 0. All players take 1 damage for each stack of Rampage. This turn, roll 2x for move and don't stop when challenging a player. Gain +1 permanent ATK and Boss Lvl x 1 HP."
- New description: "Lower Hype to 0. All players take 1 damage for each stack of Rampage. This turn, roll 2x for move and don't stop when challenging an enemy. Gain +1 permanent ATK and Boss Lvl x 1 HP."
V3.8
- Rampage no longer increases boss max HP, but has "gain Boss Lvl x 1 HP".
- Summer Beast now has a special message appear whenever gaining Hype.
- Summer Beast now warps first when using Hide And Seek.
- Sweet Heaven CO has been added for extreme difficulty Summer Beast.
