This is pretty much how a FF IV style summon works.
I made this for an acquantance but thought other beginner rpg maker 2003 users can use this too. This tutorial uses character maker 1999. You don't have to use it but that is what I use in here. If you use something else skip down to 17. The pictures are huge so excuse the massive amounts of spoilers. Step 27 does not have a picture. My bad.
1) open character maker 1999
2)click this to open files
3)Open a big monster. I opened an RTP monster
4) After its open click view and make character size = to the monster size
5)Right click on the beast. It should look like this now
6)Use this. Box the monster in the big picture.
7) Edit copy
Open a battle animation now. I used rtp battle water sheet.
9)The monster should look like this now.
10)Right click here or anywhere not attached to the monster
11)Use this sqaure filler to clear the beast!
12)Paste!!
13)Use the bucket outside the monster
14)Flip it!
15) Left click here to make the monster appear! Put him somewhere away form the other animations.
16) Save as and name it something you can remember. Save it outside the rtp! Somewhere safe.
17)Import it to battle
18) Go to animations 1 array size
19) Click animation file .. and pick your sheet!!
20) Where's my feet?
21) There it is.
22) Put him together like a puzzle in frame 1.
23)Copy frame 1
24)Paste using ctrl v like crazy for about 30 frames!
25) On some frames delete everything (4, 9, 14). Do this to make it look like he is vaporizing to the field!
26)Make him move by dragging the pieces bit by bit, frame by frame.
27)You don't have to keep moving him. Make him stop a couple of frames and then move him if you want!
28) Keep moving him and stop till desired. ( I did 30)
29) Throw in some crazy stuff and animate using the copy and paste and bit by bit method done earlier.
30)Make it epic!!
31) After you made it epic make the beast be by itself.
32 and 33) Copy that frame and paste like crazy again. (I did frames 82 to frame 98)
34) Like you did earlier in the beginning delete some frames. It will make it look like he is dissolving away.
35) Add sound at the right spots!
36)test your material
37(Make it a skill!
38) Give it to someone
39)Test it out in game. I made a test battle map area.
http://www.youtube.com/watch?v=i4xCMjIxMXY