(like phil said, is this even pixel art? some graphics in the above screencap are and some aren't. your posted blob tile certainly isn't.)
Oh I see what you're trying to do now. Geeze, it took you a few pages to communicate something pretty simple. Don't you hate it when that happens? Happens to me as well. Being concise yet properly informative is a real balance.
And oddly enough, I'm being faced with this exact same task right now, yet even more complicated because I'm attempting to create a square-tiling "total-tiling" (tiles on all four sides) texture that is supposed to emulate a fiery or electric look but that also has a leading edge because it has a beginning to it, so my tiles need to also harmoniously seam into an edge or transition tile as well, and these edge tiles that seam into the total-tiling body tiles tile with themselves vertically. It'll be like a wave of energy designed to sweep across the screen.
So you're just making a 32x32 texture designed to animate and look like some dangerous alive goo. Well mighty unrestrained beast of the unadulterated thunder and other miscellaneous atmospheric phenomena, this task can actually be pretty simple given the right tools.
I'll give you two ideas as to how you might create the desired effect, but with very robotic, non-intuitive yet delightfully functional methods.
#1
-First, think about how you want to portray the blob, don't just sit down on your computer right way and start banging out graphics with no forethought. Think first. Dig up reference material. Observe.
-Now that you've chosen how to illustrate a 32px square as slimey blobby stuff with animation in mind, create a static (1 frame; no anim . . . yet) 32x32px texture. Use full color, do not control your palette at this point, use thousands of colors if you want, auto AA, everything you wanna do, as if digi-painting.
-Tile the resulting 32px tile at least 9 times, creating a square block, so you have one fully encapsulated tile in the middle, just like your original post actually.
-Ok, now flatten the document so you've only got one layer. Now comes the sacrilege. Find a distorting filter that produces the desired throbby blobby movement you need, the filter needs to have variable controls so you can alter it's amount of effect, which is commonly called Phase.
-Create several versions of your tiled texture using this same filter but in different "phases". Because you're running a filter on a tiled texture, it's effects should be tiling as well, at least mostly.
-Now, since you're making pixel art, we need to knock the palette down to something controlled. Reduce the colors to something like 4-8 colors, depends on the rest of your game's graphics; make it integrate harmoniously. Now's also a good time to fine-tune each color after optimizing. Pick out some nice greens, try a hue shift in your ramp. Avoid maximum saturation greens like in your screencap.
-Once you've got enough filtered and optimized versions of your original texture, crop each version's inside 32x32px tile and that's what you'll feed your game-maker program. We had to work on your tile set inside of a tiled texture surounding it so that effects applied properly wrapped and affected all four sides of the tile correctly.
-But we're not done yet. You may need to touch up the edges of your tile so there aren't any obviously discernable seams to ruin the effect. Use your animation program to do this so you can test as you edit. There's a workflow to this. Find it. When doing little fixes on the edges it's also a good time to fix any internal problems. Also, it's a good time to create variations so every tiles isn't the same.
#2
-A simple hue cycle animation. Create your already optimized pixel art tile, you can use the method above if you like. And with no actual moving pixels and with just one frame you simply create frames for your animation by cycling the hue and/or lightness/darkness of all pixels equally of each frame. This is one good application for intentional pillow-shading.
That's it. You can even combine the two methods - use method 1 and throw in a little mthod 2 hue shift for some extra radioactive effect.
