Ok, here are some nice spells for you:
Cantrips:
Presdigitation - the best cantrip of them all
Ghost Sound - can create speech--and that's all you need to know
Dancing Lights - make light or vague shapes
Mage Hand - all sorts of fun
Detect Magic - know what is good to take and bad to touch
Read Magic - use scrolls
Ray of Frost - just because you can Sneak Attack with it
Light - lasts for some time. don't take it if you have darkvision (don't remember what aasimar gets)
Mending - your clothes always look good
Level 1:
Grease - the ultimate prankster spell. Also very useful in combat, since it forces a saving throw every round.
Endure Elements - not exactly in line with the prankster theme, but hugely useful: it lasts for 24 hours (great to cast on yourself and the party before going to bed). Also useful for avoiding some of the effect of certain traps
Shield - this one will keep you alive more than once
Feather Fall - might just save your life one day. Plus, you get make a show of yourself when everyone is climbing down a ladder and you just jump
Magic Missile - very good spell, even though you can't Sneak Attack with it
Other good ones here: Hold Portal (if you don't take Arcane Lock), Protection from Evil, Unseen Servant, True Strike (get a wand instead), Ventriloquism, Animate Rope.
Level 2:
Knock - a no-brainer, really
See Invisibility - this is a must-have at this level; you'll be casting it often
Alter Self - the possibilities are limitless. I would take this over Polymorph Self because you get to keep your physical stats (for you, this will be important). You can also just change one thing or two.
Arcane Lock - I love this spell, though admittedly you could just get a wand or some scrolls of it. I find it a nice trick, since you can open the door, but no one else can. You may want to take Hold Portal at 1st level, though, freeing this up for something like Mirror Image or a stat buff (Endurance is good, since Cat's Grace will be obsolete by 14th level)
Level 3:
Flame Arrow - if you focus on ranged attacks for combat
Haste - the best spell for the level. Really too good
Suggestion - if you like the persuasive side of your charisma score. If you feel you need something more combat-oriented, take Slow instead.
Don't take any big evocations: you will never do much damage with them when compared to a wizard or sorcerer of your level. Other great spells here: Dispel Magic (if you have no cleric or arcane user in the party, take this), Protection from Elements, Clairaudience/Clairvoyance, Slow, Shrink Item, Fly (you can do it with Alter Self, though poorly).
Level 4:
Improved Invisibility - another no-brainer
A researched Illusion, maybe? Something like Major Image, but with speech. If you can research that here, you could save a 3rd or 5th level spot on the illusions (those levels have more goodies IMO). If you can't, take Charm Monster, maybe, Dimension Door (if you feel you need mobility), Polymorph Other for the fort save (not really in-line with the char, but you don't have to use it on people... the knight's warhorse is more vulnerable to the effect
) or Confusion... If you want protection, take Minor Globe of Invulnerability or Stoneskin.
Level 5:
This one is entirely upto you. Telekinesis is nice, but Teleport is a must-have... Wall of Force is also a very strong spell, as is Hold Monster. Ghostform (from T&B) is a great defensive spell, and it also allows you to pass through walls and play some tricks. If you don't have an illusion by now, Persistant Image is the spell for you.
For feat, Still and Silent spell seem very fitting. Eschew Materials might also be good for you (depends on your spell selection--if you have a lot of stuff you'd like to cast undiscovered with material components, take it). Other than that, I would focus on ranged attacks, using Flame Arrow to do some extra damage.
Cantrips:
Presdigitation - the best cantrip of them all
Ghost Sound - can create speech--and that's all you need to know
Dancing Lights - make light or vague shapes
Mage Hand - all sorts of fun
Detect Magic - know what is good to take and bad to touch
Read Magic - use scrolls
Ray of Frost - just because you can Sneak Attack with it
Light - lasts for some time. don't take it if you have darkvision (don't remember what aasimar gets)
Mending - your clothes always look good
Level 1:
Grease - the ultimate prankster spell. Also very useful in combat, since it forces a saving throw every round.
Endure Elements - not exactly in line with the prankster theme, but hugely useful: it lasts for 24 hours (great to cast on yourself and the party before going to bed). Also useful for avoiding some of the effect of certain traps
Shield - this one will keep you alive more than once
Feather Fall - might just save your life one day. Plus, you get make a show of yourself when everyone is climbing down a ladder and you just jump
Magic Missile - very good spell, even though you can't Sneak Attack with it
Other good ones here: Hold Portal (if you don't take Arcane Lock), Protection from Evil, Unseen Servant, True Strike (get a wand instead), Ventriloquism, Animate Rope.
Level 2:
Knock - a no-brainer, really
See Invisibility - this is a must-have at this level; you'll be casting it often
Alter Self - the possibilities are limitless. I would take this over Polymorph Self because you get to keep your physical stats (for you, this will be important). You can also just change one thing or two.
Arcane Lock - I love this spell, though admittedly you could just get a wand or some scrolls of it. I find it a nice trick, since you can open the door, but no one else can. You may want to take Hold Portal at 1st level, though, freeing this up for something like Mirror Image or a stat buff (Endurance is good, since Cat's Grace will be obsolete by 14th level)
Level 3:
Flame Arrow - if you focus on ranged attacks for combat
Haste - the best spell for the level. Really too good
Suggestion - if you like the persuasive side of your charisma score. If you feel you need something more combat-oriented, take Slow instead.
Don't take any big evocations: you will never do much damage with them when compared to a wizard or sorcerer of your level. Other great spells here: Dispel Magic (if you have no cleric or arcane user in the party, take this), Protection from Elements, Clairaudience/Clairvoyance, Slow, Shrink Item, Fly (you can do it with Alter Self, though poorly).
Level 4:
Improved Invisibility - another no-brainer
A researched Illusion, maybe? Something like Major Image, but with speech. If you can research that here, you could save a 3rd or 5th level spot on the illusions (those levels have more goodies IMO). If you can't, take Charm Monster, maybe, Dimension Door (if you feel you need mobility), Polymorph Other for the fort save (not really in-line with the char, but you don't have to use it on people... the knight's warhorse is more vulnerable to the effect
) or Confusion... If you want protection, take Minor Globe of Invulnerability or Stoneskin.Level 5:
This one is entirely upto you. Telekinesis is nice, but Teleport is a must-have... Wall of Force is also a very strong spell, as is Hold Monster. Ghostform (from T&B) is a great defensive spell, and it also allows you to pass through walls and play some tricks. If you don't have an illusion by now, Persistant Image is the spell for you.
For feat, Still and Silent spell seem very fitting. Eschew Materials might also be good for you (depends on your spell selection--if you have a lot of stuff you'd like to cast undiscovered with material components, take it). Other than that, I would focus on ranged attacks, using Flame Arrow to do some extra damage.
