you throw a boomarang and it comes back.

[Lauli]

Boomerang (returning version) summons t0 objects every single frame (t0 objects delete themselves after leaving their first frames (wait: 1?)).
Summoner catches t0 object summoned by Boomerang (r.v.).
Boomerang (r.v.) reacts with ik:8 to caught t0 and deletes itself.
t0 object shows Boomerang sprites.
Summoner deletes t0 'fake' Boomerang and opoint+wpoint (you know - summoning a weapon and holding it.) original Boomerang.

Guy virtually "hits" the boomarang (=destroys it) and creates some fake stuff then.
Like Clews attack

OR

The boomerang reacts with itr/kind: 8 directly to the char.


Easier I'd say.