Selfmates with active white king 2

1.Sd1! zz
1...exd1Q+ 2.Kh3 Qg4#
1...exd1R+ 2.Kf3 Rd3#
1...exd1B+ 2.Kh1 Bf3#
1...exd1S+ 2.Kf1 Se3#

The key provokes 4 checks to wK by 4 promotions and White responds to them by a star of wK.

1.LEb7! th. 2.LEc8+ Kxd7#
1...VAxh3 2.Kxc2+ Kf5#
1...exf4 2.Kb2+ Ke5#
1...e4 2.Kb4+ Kd6#

The threat involves black royal battery, in defences Black provides wK flights, however White uses them for firing his own royal battery and forcing mate by black direct antibattery and indirect royal battery.

1.g5! zz
1...Rg3 2.Kc4 Ra3 3.Rxh4+ Qxh4#
1...Rxc7 2.Kd3 Rc1 3.Bxd7+ Qxd7#
1...Ra5 2.Ke4 Rxg5 3.Rxh4+ Qxh4#
1...Re1 2.Kd5 Re8 3.Bxd7+ Qxd7#

Unified play in 4 variations of a maximummer is introduced by rook moves and this way allowed cross of white King. 3 out of 4 mates are model, but they are all of the same kind. A bit mechanical, but well thought up.

1.g3! zz
1...S~ 2.Re8+ Kxe8 3.Bxd2 Bxf6#
1...Se6! 2.Kb3 Bxf6 3.Bc5+ Sxc5#
1...Sf7! 2.Kc4 Bxf6 3.Bc5+ Sd6#
1...Sxe4+! 2.Kb2 Bxf6+ 3.Sc3 Bxc3#

Original combination of ideas. As usually in maximummers, free bS with no longer move available means variations. Here there is prepared continuation to a random knight move with check on a long diagonal, however, bS can correct its move - and in 3 different ways! Two variations are very similar, leading after closing of bishop line to doublecheck model, the remaining correction introduces a bit different mate. All three mates that finish correction variations are models, two of them in a nice echo.

1.Qb4! zz
1...Qg8 2.Kc1 Qxa2 3.Qb3 Sxb3#
1...Qa8 2.Qf8+ Qxf8 3.Kc1 Qa3#
1...Qxg2 2.Kc1 Qa8 3.Qb2 Qh1#
1...Qxa2+ 2.Kc3 Qg8 3.Qb3 Qxb3#

Here there are 4 variations as well, but their beginnings are different, it is the big star of black Queen. Also the mates aren't model...

1.Rh4! zz
1...cxb5 2.Kc2 b4 3.Rc4 b3#
1...c5 2.Kd2 c4 3.Rd4 c3#
1...cxd5 2.Ke2 d4 3.Re4 d3#

The key by rook is a long anticritical move - and White waits for Black... the first black move determines the file where the mate will appear afterwards. This selfmate reminds me of my own s#4 with royal lion, where White waits too. There, however, there are only 2 chameleon echo model mates, here you can find 3!

1.h5! zz
1...Gd5 2.Kc3 Ga8 3.CAab2 Ga3#
1...Gd1 2.Ka3 Gh1 3.(1,5)b2 Ga1#
1...Gh1 2.Ka1 Gh6 3.CAeb2 Gc1#
1...Gxh5 2.Kc1 Gh8 3.Sb2 Gc3#

A problem full of formal themes. The first black moves from a star of a grasshopper, the 2nd white moves from a star of a king. Then in 3rd move White blocks 4 times b2 by 4 different pieces (pity, that choice of piece is 3 times motivated by line opening and once by unguard). Black grasshopper visits all 4 corners of the board and there is also a cycle of squares where wK and mating bG stand in mates.