Is targeting a spell part of the spell casting or after the spell is sucessfully cast

[Stephen Ede]

The Dweomer Cat/Cub has the ability to teleport adjacent to a Spellcaster targeting them with a spell and make a full attack upon them. -

Dweomer Leap (Su)

When a dweomercat cub is targeted by a spell or within the area of effect of a spell, it can, as an immediate action, choose to teleport to a square adjacent to the spell’s caster, effectively appearing mid-leap and aimed toward the caster. This ability takes effect regardless of whether or not the spell overcomes the dweomercat cub’s spell resistance. If it chooses, the dweomercat cub can immediately make a full attack against the spell’s caster as though pouncing. Using this ability does not provoke an attack of opportunity. If there is no safe space adjacent to the caster—or if the dweomercat cub's chooses—the dweomercat cub can forgo using this ability.

-------------

The question is does this interrupt the spell such that any damage dealt requires a Concentration check to avoid the spell failing, or does it occur after the spell has been cast but before the spell hits, or while the spell is still been cast and thus capable of disrupting the spell.

Thanks

[RumpinRufus]

I think the order goes:

1) Spell is declared and targeted
2) Dweomercat gets to pounce in response to being targeted
3) The rest of the spell is resolved (concentration checks, SR, saves, effects, etc.)

[Jeff Merola]

From the magic section:
"Target or Targets: Some spells have a target or targets. You cast these spells on creatures or objects, as defined by the spell itself. You must be able to see or touch the target, and you must specifically choose that target. You do not have to select your target until you finish casting the spell."