Make an advanced powder toy lua mod that adds a pythonic solid, it's really durable and has uni-frame, and subframe regeneration. It'll have an interesting special property that'll expand inwards when a frame of itself is damaged.

Example Lua Mod, (THIS IS ONLY AN EXAMPLE. MAKE YOUR OWN LUA SCRIPT)

Reference Script (REFERENCE ONLY):

```
local antidest = elements.allocate("antidestruct", "anti")
elements.element(antidest, elements.element(elements.DEFAULT_PT_LIFE))

elements.property(antidest, "Name", "ANCL")
elements.property(antidest, "Description", "Anti-destructive self-repairing cell. Regenerates quickly and slowly populates.")
elements.property(antidest, "Colour", 0x00FF00)
elements.property(antidest, "MenuSection", elem.SC_LIFE)
elements.property(antidest, "Properties", elem.TYPE_SOLID + elem.PROP_LIFE)

local function update(i, x, y, s, nt)
    -- Ultra-fast self-repair
    sim.partProperty(i, "life", math.min(sim.partProperty(i, "life") + 5, 100)) -- Regenerates faster
    
    -- Repair damaged particles around it quickly
    for rx = -1, 1 do
        for ry = -1, 1 do
            local r = sim.pmap(x + rx, y + ry)
            if r then
                local rtype = sim.partProperty(r, "type")
                if rtype == antidest then
                    sim.partProperty(r, "life", math.min(sim.partProperty(r, "life") + 5, 100)) -- Heal neighbors faster
                end
            end
        end
    end

    -- Immune to destruction and bombs: neutralize nearby destructive elements instantly
    for rx = -2, 2 do
        for ry = -2, 2 do
            local r = sim.pmap(x + rx, y + ry)
            if r then
                local rtype = sim.partProperty(r, "type")
                if rtype == elem.DEFAULT_PT_DEST or rtype == elem.DEFAULT_PT_BOMB or rtype == elem.DEFAULT_PT_FIRE or rtype == elem.DEFAULT_PT_AMTR or rtype == elem.DEFAULT_PT_THDR or rtype == elem.DEFAULT_PT_SING or rtype == elem.DEFAULT_PT_SRAD or rtype == elem.DEFAULT_PT_SMDB then
                    sim.partKill(r) -- Completely destroy nearby harmful particles
                end
            end
        end
    end
    
    -- Slow population growth
    if math.random() < 0.01 then
        local nx, ny = x + math.random(-1, 1), y + math.random(-1, 1)
        if not sim.pmap(nx, ny) then
            sim.partCreate(-1, nx, ny, antidest)
        end
    end
    
    -- Resist pressure and temperature changes
    sim.pressure(x / 4, y / 4, (sim.pressure(x / 4, y / 4) + 1) / 2)
    sim.partProperty(i, "temp", 295.15)  -- Maintain room temperature
end

elements.property(antidest, "Update", update)
```

Other References:

```
local smfb = elements.allocate("smallfubomb", "smfb")
elements.element(smfb, elements.element(elements.DEFAULT_PT_DEST))

elements.property(smfb, "Name", "SMFB")
elements.property(smfb, "Description", "Small Mother F***ing bomb. VERY DESTRUCTIVE")
elements.property(smfb, "Temperature", 273.15)
elements.property(smfb, "HeatConduct", 255)
elements.property(smfb, "Weight", 500)

local function explosion(i,x,y,s,nt)
	for r in sim.neighbors(x,y,1,1) do
		if sim.partProperty(r, "type") ~= smfb then
			sim.partProperty(r, "temp", 10000)
			sim.pressure(x/4, y/4, sim.pressure(x/4, y/4) + 10)
			if sim.partProperty(i, "life") == 0 then
				sim.partProperty(i, "life", 301)
			end
			if math.random(0, math.random(1, 25)) == 0 then
				sim.partChangeType(r, elem.DEFAULT_PT_HYGN)
			end
			if math.random(0, 50) == 0 then
				sim.partProperty(r, "life", 0)
				sim.partChangeType(r, smfb)
			end
			if math.random(0, 100) == 0 then
				sim.partChangeType(r, elem.DEFAULT_PT_DEST)
			end
			if math.random(0, 50) == 0 then
				sim.partChangeType(r, elem.DEFAULT_PT_GBMB)
			end
			if math.random(0, 50) == 0 then
			    sim.partProperty(r, "tmp2", 10000)
			    sim.partProperty(r, "life", 1000)
			    sim.partChangeType(r,elem.DEFAULT_PT_WARP)
			end
			local ix = math.random(sim.partProperty(r, "x") - 1, sim.partProperty(r, "x") + 1)
			local iy = math.random(sim.partProperty(r, "y") - 1, sim.partProperty(r, "y") + 1)
			sim.partProperty(i, "x", ix)
			sim.partProperty(i, "y", iy)
		end
		if sim.partProperty(i, "life") < 61 and sim.partProperty(i, "life") ~= 0 then
			sim.partChangeType(r, elem.DEFAULT_PT_BOMB)
		end
		sim.partProperty(i, "vx", math.random(sim.partProperty(i, "vx") - 5, sim.partProperty(i, "vx") + 5))
		sim.partProperty(i, "vy", math.random(sim.partProperty(i, "vy") - 5, sim.partProperty(i, "vy") + 5))
	end
end

elements.property(smfb, "Update", explosion)