This enemy base can attack cat units in range with a slow attack rate. Because it is a base, it does not move, similar to the Sun Doge and Drummer Doge. All of its attacks are instant-kill, although Glass Cat and Metal Cat can survive due to having the Metalability. Like Scarecrow, this enemy is immune to all abilities because it is an enemy base.
Basically any unit that it can outrange, it will kill. Therefore, the best way to counter the 7th Anniversary Scarecrow is to use units that outrange it, or time your units so that they go directly before the 7th Anniversary Scarecrow attacks so your units can trigger the next wave as fast as possible, as the boss wave knocks your units out of the 7th Anniversary Scarecrow's range.
7th Anniversary Scarecrow
999,999 damage (49,261.03 DPS)
300 (area attack)
10f (27f backswing)
Immune to all negative effects
7th Anniverasry Scarecrows appearance in BCJP
In reality, the Scarecrow’s health is not infinite as the chart above shows. It actually has 100 hp, but takes no damage, giving the impression that it has infinite health.