Merge

For the merging of Mega Monkeys, see Mega Monkeys.

“	Upgrade to a Tier 2 beast, then use the Beast Handler's Merge button. Select another Beast Handler to make the combined Beast stronger!	”
	^{~ Patch's advice on the "Epic Beast Quest" Quest 1}

Merge is a targeting priority exclusive to the Beast Handler. It merges weaker-tier beasts into stronger-tier beasts. Doing so transfers energy, up to a local maximum of stored energy; contributed merge beast will combine with each other, in other words, contributed Beast Handler will sacrifices to host Beast Handler, doing this merged beasts can become stronger by having a higher beast power. Having a higher beast power increases many of its base statistics, particularly pierce, attack speed, damage, and ability cooldowns for middle path upgrade, some of merged beast can increase their popping-power attack, maximum beast power merged beast can even allow targeting or Instakilling certain bloons or getting new popping-power.

Range which also got transfers, in which contributing Beast Handlers "share" ranges for that beast, essentially expanding the placeable range of that beast. All contributing Bird Handlers add range for birds, whereas the contributing Fish and Dino Handlers must overlap ranges with the host Beast Handler in order to count as extra range.

Beast Handlers can merge beasts into Tier 2 or above beasts, as these beasts each have more than 1 beast power. "Beast power" is essentially a unit of beast strength that builds up as the beast gains more tiers or is merged with more beasts of equal or lower tier (except Tier 5, which cannot accept other Tier 5 beasts).

As beasts gain higher power, their physical appearance changes at max power, and sometimes also at an intermediate amount of power not necessarily equal to halfway between min and max power. The following visual changes to the beasts occur at T2 and above:

T2: 3/6, 6/6
T3: 8/24, 16/24, 24/24
T4: 16/64, 36/64, 64/64
T5: 36/132, 100/132, 132/132

Sounds

When a Beast Handler merges beasts:

[???]

Gallery

In-game assets

Trivia

The capability to merge is similar to the Merge genre of mobile games.
This system operates similarly to the Paragons mechanics; both are sacrifices same category transforming into strong one, so it could be valid to refer this as obtaining a Mini Paragon.