Anarchy!

[OdinVanguard]

Anarchy! / Bedlam!
Cost: 4 / 5
Stats (if creature or weapon): -NA-
Ability(ies):

• unupgraded: "All creatures in play (on both sides) use their activateable abilities randomly then attack."
• upgraded: "All creatures and permanents in play (on both sides) use their activateable abilities randomly, all creatures attack."

Activateable abilities get used on random targets (if targeting is needed). Attacks happen after abilities are used, so this also re-readies all abilities. Abilities used in this way are played for free (no cost is payed), however, those that require a sacrifice will still do so (at random).

[Dawn to Dusk]

so you can use abilities 3 times? (once at the beginning of the turn, play anarchy, use ability again)
seems abusable with pharaoh but idk

[Lost in Nowhere]

Well, with that, it a) requires a ton of quanta, and b) the scarabs will very quickly begin eating the pharaohs (and each other).

[OdinVanguard]

Well, with that, it a) requires a ton of quanta, and b) the scarabs will very quickly begin eating the pharaohs (and each other).

^exactly

In fact part of the motivation was as a way to deter the proliferation of decks that spam 'on a stick' abilities.

Creatures that don't target things would be safe (lava golems or Physalias for example). Most creatures would have at least some chance to backfire though.
E.g. byt could buff your opponent's stuff, purple nymphs could AM your own creatures, mind flayers could self lobo, etc.
Quintecence could be very useful here but that would start getting expensive. Especially since you couldn't use any quint on a stick type cards without risking quinting your opponent's stuff as well.