Learn Croatian: Kada budem vidio kameleona, pokazat ću ti ga. - When I see a chameleon, I will show it to you.

Budem vidio is the Future Exact tense (Futur II). In Croatian, when you are talking about a future condition that must be fulfilled before the main future action happens (showing the chameleon), you use Futur II after conjunctions like kada or ako. While you will often hear native speakers use the present tense (Kada vidim...) in everyday speech, budem vidio is the most grammatically precise way to show this sequence.

Why does kameleon take the -a ending here to become kameleona?

Here it acts as the direct object of the verb, so it must be in the accusative case. Because kameleon is a masculine noun representing a living creature, it follows the animate rule: its accusative form matches its genitive form, taking the -a ending.

Could I write pokazati ću instead of pokazat ću?

Grammatically, no. When the future tense auxiliary verb (like ću) directly follows an infinitive ending in -ti, you must drop the final i in both writing and speaking. If you change the word order to put the auxiliary first, the full infinitive is used instead: ja ću ti ga pokazati.

What dictates the order of the short words ti and ga at the end of the sentence?